61381620 has 72 divisors (see below), whose sum is σ = 187989984. Its totient is φ = 16210368.

The previous prime is 61381613. The next prime is 61381627. The reversal of 61381620 is 2618316.

61381620 is a `hidden beast` number, since 6 + 1 + 38 + 1 + 620 = 666.

It is an interprime number because it is at equal distance from previous prime (61381613) and next prime (61381627).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61381627) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17667 + ... + 20853.

It is an arithmetic number, because the mean of its divisors is an integer number (2610972).

Almost surely, 2^61381620 is an apocalyptic number.

61381620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61381620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93994992).

61381620 is an abundant number, since it is smaller than the sum of its proper divisors (126608364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61381620 is a wasteful number, since it uses less digits than its factorization.

61381620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3309 (or 3304 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 61381620 is about 7834.6423019816. The cubic root of 61381620 is about 394.4689118519.

Adding to 61381620 its reverse (2618316), we get a palindrome (63999936).

It can be divided in two parts, 61381 and 620, that added together give a square (62001 = 249²).

The spelling of 61381620 in words is "sixty-one million, three hundred eighty-one thousand, six hundred twenty".