61955820 has 144 divisors (see below), whose sum is σ = 205272480. Its totient is φ = 15510528.

The previous prime is 61955783. The next prime is 61955821. The reversal of 61955820 is 2855916.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (61955821) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 155862 + ... + 156258.

Almost surely, 2^61955820 is an apocalyptic number.

61955820 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 61955820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102636240).

61955820 is an abundant number, since it is smaller than the sum of its proper divisors (143316660).

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

61955820 is a wasteful number, since it uses less digits than its factorization.

61955820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449 (or 424 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 61955820 is about 7871.2019412540. The cubic root of 61955820 is about 395.6951280639.

The spelling of 61955820 in words is "sixty-one million, nine hundred fifty-five thousand, eight hundred twenty".