21602992921 has 2 divisors, whose sum is σ = 21602992922. Its totient is φ = 21602992920.

The previous prime is 21602992877. The next prime is 21602992927. The reversal of 21602992921 is 12929920612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20353016896 + 1249976025 = 142664^2 + 35355^2 .

It is a cyclic number.

It is not a de Polignac number, because 21602992921 - 2¹³ = 21602984729 is a prime.

It is a super-3 number, since 3×21602992921³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21602992927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10801496460 + 10801496461.

It is an arithmetic number, because the mean of its divisors is an integer number (10801496461).

Almost surely, 2^21602992921 is an apocalyptic number.

It is an amenable number.

21602992921 is a deficient number, since it is larger than the sum of its proper divisors (1).

21602992921 is an equidigital number, since it uses as much as digits as its factorization.

21602992921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 43.

The spelling of 21602992921 in words is "twenty-one billion, six hundred two million, nine hundred ninety-two thousand, nine hundred twenty-one".