21437813693 has 16 divisors (see below), whose sum is σ = 21798806400. Its totient is φ = 21080347200.

The previous prime is 21437813689. The next prime is 21437813699. The reversal of 21437813693 is 39631873412.

It is a cyclic number.

It is not a de Polignac number, because 21437813693 - 2² = 21437813689 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21437813699) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11518583 + ... + 11520443.

It is an arithmetic number, because the mean of its divisors is an integer number (1362425400).

Almost surely, 2^21437813693 is an apocalyptic number.

It is an amenable number.

21437813693 is a deficient number, since it is larger than the sum of its proper divisors (360992707).

21437813693 is a wasteful number, since it uses less digits than its factorization.

21437813693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2708.

The product of its digits is 653184, while the sum is 47.

The spelling of 21437813693 in words is "twenty-one billion, four hundred thirty-seven million, eight hundred thirteen thousand, six hundred ninety-three".