21697050979 has 2 divisors, whose sum is σ = 21697050980. Its totient is φ = 21697050978.

The previous prime is 21697050923. The next prime is 21697051009. The reversal of 21697050979 is 97905079612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21697050979 - 2³³ = 13107116387 is a prime.

It is not a weakly prime, because it can be changed into another prime (21697050079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10848525489 + 10848525490.

It is an arithmetic number, because the mean of its divisors is an integer number (10848525490).

Almost surely, 2^21697050979 is an apocalyptic number.

21697050979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21697050979 is an equidigital number, since it uses as much as digits as its factorization.

21697050979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2143260, while the sum is 55.

The spelling of 21697050979 in words is "twenty-one billion, six hundred ninety-seven million, fifty thousand, nine hundred seventy-nine".