90887878921 has 4 divisors (see below), whose sum is σ = 103871861632. Its totient is φ = 77903896212.

The previous prime is 90887878919. The next prime is 90887878943. The reversal of 90887878921 is 12987878809.

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 90887878921 - 2¹ = 90887878919 is a prime.

It is a super-2 number, since 2×90887878921² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (90887878951) 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, 6491991345 + ... + 6491991358.

It is an arithmetic number, because the mean of its divisors is an integer number (25967965408).

Almost surely, 2^90887878921 is an apocalyptic number.

It is an amenable number.

90887878921 is a deficient number, since it is larger than the sum of its proper divisors (12983982711).

90887878921 is a wasteful number, since it uses less digits than its factorization.

90887878921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12983982710.

The product of its (nonzero) digits is 32514048, while the sum is 67.

The spelling of 90887878921 in words is "ninety billion, eight hundred eighty-seven million, eight hundred seventy-eight thousand, nine hundred twenty-one".