20921569967 has 2 divisors, whose sum is σ = 20921569968. Its totient is φ = 20921569966.

The previous prime is 20921569939. The next prime is 20921569973. The reversal of 20921569967 is 76996512902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20921569967 - 2²⁴ = 20904792751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20921569927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10460784983 + 10460784984.

It is an arithmetic number, because the mean of its divisors is an integer number (10460784984).

Almost surely, 2^20921569967 is an apocalyptic number.

20921569967 is a deficient number, since it is larger than the sum of its proper divisors (1).

20921569967 is an equidigital number, since it uses as much as digits as its factorization.

20921569967 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3674160, while the sum is 56.

The spelling of 20921569967 in words is "twenty billion, nine hundred twenty-one million, five hundred sixty-nine thousand, nine hundred sixty-seven".