19621811979 has 128 divisors (see below), whose sum is σ = 36957634560. Its totient is φ = 9993715200.

The previous prime is 19621811903. The next prime is 19621811983. The reversal of 19621811979 is 97911812691.

19621811979 is a `hidden beast` number, since 1 + 9 + 621 + 8 + 1 + 1 + 9 + 7 + 9 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-19621811979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19621811999) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 45315747 + ... + 45316179.

It is an arithmetic number, because the mean of its divisors is an integer number (288731520).

Almost surely, 2^19621811979 is an apocalyptic number.

19621811979 is a deficient number, since it is larger than the sum of its proper divisors (17335822581).

19621811979 is a wasteful number, since it uses less digits than its factorization.

19621811979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 838 (or 832 counting only the distinct ones).

The product of its digits is 489888, while the sum is 54.

The spelling of 19621811979 in words is "nineteen billion, six hundred twenty-one million, eight hundred eleven thousand, nine hundred seventy-nine".