61187531631 has 4 divisors (see below), whose sum is σ = 81583375512. Its totient is φ = 40791687752.

The previous prime is 61187531617. The next prime is 61187531651. The reversal of 61187531631 is 13613578116.

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

It is a cyclic number.

It is not a de Polignac number, because 61187531631 - 2⁵ = 61187531599 is a prime.

It is a super-2 number, since 2×61187531631² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61187531611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10197921936 + ... + 10197921941.

It is an arithmetic number, because the mean of its divisors is an integer number (20395843878).

Almost surely, 2^61187531631 is an apocalyptic number.

61187531631 is a deficient number, since it is larger than the sum of its proper divisors (20395843881).

61187531631 is a wasteful number, since it uses less digits than its factorization.

61187531631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20395843880.

The product of its digits is 90720, while the sum is 42.

The spelling of 61187531631 in words is "sixty-one billion, one hundred eighty-seven million, five hundred thirty-one thousand, six hundred thirty-one".