61805631 has 4 divisors (see below), whose sum is σ = 82407512. Its totient is φ = 41203752.

The previous prime is 61805629. The next prime is 61805677. The reversal of 61805631 is 13650816.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 61805631 - 2¹ = 61805629 is a prime.

It is a super-2 number, since 2×61805631² = 7639872046616322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61805621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10300936 + ... + 10300941.

It is an arithmetic number, because the mean of its divisors is an integer number (20601878).

Almost surely, 2^61805631 is an apocalyptic number.

61805631 is a deficient number, since it is larger than the sum of its proper divisors (20601881).

61805631 is a wasteful number, since it uses less digits than its factorization.

61805631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20601880.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 61805631 is about 7861.6557416361. The cubic root of 61805631 is about 395.3751304612.

It can be divided in two parts, 6180 and 5631, that added together give a palindrome (11811).

The spelling of 61805631 in words is "sixty-one million, eight hundred five thousand, six hundred thirty-one".