21231645357 has 16 divisors (see below), whose sum is σ = 30829014720. Its totient is φ = 12918820992.

The previous prime is 21231645353. The next prime is 21231645401. The reversal of 21231645357 is 75354613212.

It is not a de Polignac number, because 21231645357 - 2² = 21231645353 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231645353) 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, 3054963 + ... + 3061904.

It is an arithmetic number, because the mean of its divisors is an integer number (1926813420).

Almost surely, 2^21231645357 is an apocalyptic number.

It is an amenable number.

21231645357 is a deficient number, since it is larger than the sum of its proper divisors (9597369363).

21231645357 is a wasteful number, since it uses less digits than its factorization.

21231645357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6116972.

The product of its digits is 151200, while the sum is 39.

The spelling of 21231645357 in words is "twenty-one billion, two hundred thirty-one million, six hundred forty-five thousand, three hundred fifty-seven".