61431163557 has 4 divisors (see below), whose sum is σ = 81908218080. Its totient is φ = 40954109036.

The previous prime is 61431163537. The next prime is 61431163561. The reversal of 61431163557 is 75536113416.

It is a happy number.

61431163557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61431163557 - 2⁸ = 61431163301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61431163537) 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, 10238527257 + ... + 10238527262.

It is an arithmetic number, because the mean of its divisors is an integer number (20477054520).

Almost surely, 2^61431163557 is an apocalyptic number.

It is an amenable number.

61431163557 is a deficient number, since it is larger than the sum of its proper divisors (20477054523).

61431163557 is a wasteful number, since it uses less digits than its factorization.

61431163557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20477054522.

The product of its digits is 226800, while the sum is 42.

The spelling of 61431163557 in words is "sixty-one billion, four hundred thirty-one million, one hundred sixty-three thousand, five hundred fifty-seven".