21660651511 has 8 divisors (see below), whose sum is σ = 22604396544. Its totient is φ = 20717071320.

The previous prime is 21660651487. The next prime is 21660651517. The reversal of 21660651511 is 11515606612.

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 21660651511 - 2¹⁵ = 21660618743 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 (21660651517) 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, 281010 + ... + 349696.

It is an arithmetic number, because the mean of its divisors is an integer number (2825549568).

Almost surely, 2^21660651511 is an apocalyptic number.

21660651511 is a deficient number, since it is larger than the sum of its proper divisors (943745033).

21660651511 is a wasteful number, since it uses less digits than its factorization.

21660651511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82421.

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 21660651511 in words is "twenty-one billion, six hundred sixty million, six hundred fifty-one thousand, five hundred eleven".