61551620 has 24 divisors (see below), whose sum is σ = 139201944. Its totient is φ = 22726656.

The previous prime is 61551593. The next prime is 61551631. The reversal of 61551620 is 2615516.

It can be written as a sum of positive squares in 4 ways, for example, as 586756 + 60964864 = 766^2 + 7808^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 61551620.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118109 + ... + 118628.

It is an arithmetic number, because the mean of its divisors is an integer number (5800081).

Almost surely, 2^61551620 is an apocalyptic number.

It is an amenable number.

61551620 is an abundant number, since it is smaller than the sum of its proper divisors (77650324).

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

61551620 is a wasteful number, since it uses less digits than its factorization.

61551620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236759 (or 236757 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 61551620 is about 7845.4840513508. The cubic root of 61551620 is about 394.8327444426.

The spelling of 61551620 in words is "sixty-one million, five hundred fifty-one thousand, six hundred twenty".