61561872 has 30 divisors (see below), whose sum is σ = 172288142. Its totient is φ = 20520576.

The previous prime is 61561831. The next prime is 61561873. The reversal of 61561872 is 27816516.

It can be written as a sum of positive squares in only one way, i.e., 49617936 + 11943936 = 7044^2 + 3456^2 .

It is a super-3 number, since 3×61561872³ (a number of 24 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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 (61561873) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 213613 + ... + 213900.

Almost surely, 2^61561872 is an apocalyptic number.

It is an amenable number.

61561872 is an abundant number, since it is smaller than the sum of its proper divisors (110726270).

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

61561872 is a wasteful number, since it uses less digits than its factorization.

61561872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427527 (or 427518 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 61561872 is about 7846.1373936479. The cubic root of 61561872 is about 394.8546642588.

The spelling of 61561872 in words is "sixty-one million, five hundred sixty-one thousand, eight hundred seventy-two".