19621659523 has 16 divisors (see below), whose sum is σ = 20332840320. Its totient is φ = 18925231104.

The previous prime is 19621659493. The next prime is 19621659527. The reversal of 19621659523 is 32595612691.

It is a cyclic number.

It is not a de Polignac number, because 19621659523 - 2²⁵ = 19588105091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19621659527) 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, 965515 + ... + 985627.

It is an arithmetic number, because the mean of its divisors is an integer number (1270802520).

Almost surely, 2^19621659523 is an apocalyptic number.

19621659523 is a deficient number, since it is larger than the sum of its proper divisors (711180797).

19621659523 is a wasteful number, since it uses less digits than its factorization.

19621659523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20478.

The product of its digits is 874800, while the sum is 49.

The spelling of 19621659523 in words is "nineteen billion, six hundred twenty-one million, six hundred fifty-nine thousand, five hundred twenty-three".