18881097631 has 4 divisors (see below), whose sum is σ = 20597561064. Its totient is φ = 17164634200.

The previous prime is 18881097623. The next prime is 18881097649. The reversal of 18881097631 is 13679018881.

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 18881097631 - 2³ = 18881097623 is a prime.

It is a super-2 number, since 2×18881097631² (a number of 21 digits) 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 (18881097671) 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, 858231700 + ... + 858231721.

It is an arithmetic number, because the mean of its divisors is an integer number (5149390266).

Almost surely, 2^18881097631 is an apocalyptic number.

18881097631 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18881097631 is a deficient number, since it is larger than the sum of its proper divisors (1716463433).

18881097631 is a wasteful number, since it uses less digits than its factorization.

18881097631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1716463432.

The product of its (nonzero) digits is 580608, while the sum is 52.

The spelling of 18881097631 in words is "eighteen billion, eight hundred eighty-one million, ninety-seven thousand, six hundred thirty-one".