21723757651 has 8 divisors (see below), whose sum is σ = 21749711760. Its totient is φ = 21697821792.

The previous prime is 21723757637. The next prime is 21723757667. The reversal of 21723757651 is 15675732712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21723757651 - 2¹³ = 21723749459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21723757051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5535576 + ... + 5539498.

It is an arithmetic number, because the mean of its divisors is an integer number (2718713970).

Almost surely, 2^21723757651 is an apocalyptic number.

21723757651 is a deficient number, since it is larger than the sum of its proper divisors (25954109).

21723757651 is a wasteful number, since it uses less digits than its factorization.

21723757651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9125.

The product of its digits is 617400, while the sum is 46.

The spelling of 21723757651 in words is "twenty-one billion, seven hundred twenty-three million, seven hundred fifty-seven thousand, six hundred fifty-one".