61556390 has 64 divisors (see below), whose sum is σ = 137687040. Its totient is φ = 19336320.

The previous prime is 61556387. The next prime is 61556399. The reversal of 61556390 is 9365516.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 61556390.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61556399) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40484 + ... + 41976.

It is an arithmetic number, because the mean of its divisors is an integer number (2151360).

Almost surely, 2^61556390 is an apocalyptic number.

61556390 is an abundant number, since it is smaller than the sum of its proper divisors (76130650).

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

61556390 is a wasteful number, since it uses less digits than its factorization.

61556390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557.

The product of its (nonzero) digits is 24300, while the sum is 35.

The square root of 61556390 is about 7845.7880420006. The cubic root of 61556390 is about 394.8429434894.

The spelling of 61556390 in words is "sixty-one million, five hundred fifty-six thousand, three hundred ninety".