21387616494 has 16 divisors (see below), whose sum is σ = 45026561280. Its totient is φ = 6753984120.

The previous prime is 21387616463. The next prime is 21387616531. The reversal of 21387616494 is 49461678312.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93805222 + ... + 93805449.

It is an arithmetic number, because the mean of its divisors is an integer number (2814160080).

Almost surely, 2^21387616494 is an apocalyptic number.

21387616494 is an abundant number, since it is smaller than the sum of its proper divisors (23638944786).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21387616494 is a wasteful number, since it uses less digits than its factorization.

21387616494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187610695.

The product of its digits is 1741824, while the sum is 51.

The spelling of 21387616494 in words is "twenty-one billion, three hundred eighty-seven million, six hundred sixteen thousand, four hundred ninety-four".