61581918 has 32 divisors (see below), whose sum is σ = 127008000. Its totient is φ = 19893440.

The previous prime is 61581913. The next prime is 61581931. The reversal of 61581918 is 81918516.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61581913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40333 + ... + 41831.

It is an arithmetic number, because the mean of its divisors is an integer number (3969000).

Almost surely, 2^61581918 is an apocalyptic number.

61581918 is an abundant number, since it is smaller than the sum of its proper divisors (65426082).

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

61581918 is a wasteful number, since it uses less digits than its factorization.

61581918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1712.

The product of its digits is 17280, while the sum is 39.

The square root of 61581918 is about 7847.4147335285. The cubic root of 61581918 is about 394.8975176103.

The spelling of 61581918 in words is "sixty-one million, five hundred eighty-one thousand, nine hundred eighteen".