21660973502 has 16 divisors (see below), whose sum is σ = 37603138560. Its totient is φ = 9165764088.

The previous prime is 21660973501. The next prime is 21660973513. The reversal of 21660973502 is 20537906612.

It is a super-2 number, since 2×21660973502² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21660973502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660973501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9791378 + ... + 9793589.

It is an arithmetic number, because the mean of its divisors is an integer number (2350196160).

Almost surely, 2^21660973502 is an apocalyptic number.

21660973502 is a deficient number, since it is larger than the sum of its proper divisors (15942165058).

21660973502 is a wasteful number, since it uses less digits than its factorization.

21660973502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19585055.

The product of its (nonzero) digits is 136080, while the sum is 41.

The spelling of 21660973502 in words is "twenty-one billion, six hundred sixty million, nine hundred seventy-three thousand, five hundred two".