21001010021969 has 2 divisors, whose sum is σ = 21001010021970. Its totient is φ = 21001010021968.

The previous prime is 21001010021947. The next prime is 21001010022037. The reversal of 21001010021969 is 96912001010012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18408072754369 + 2592937267600 = 4290463^2 + 1610260^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001010021969 - 2³⁶ = 20932290545233 is a prime.

It is a super-2 number, since 2×21001010021969² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21001010029969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500505010984 + 10500505010985.

It is an arithmetic number, because the mean of its divisors is an integer number (10500505010985).

Almost surely, 2^{21001010021969} is an apocalyptic number.

It is an amenable number.

21001010021969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001010021969 is an equidigital number, since it uses as much as digits as its factorization.

21001010021969 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 32.

The spelling of 21001010021969 in words is "twenty-one trillion, one billion, ten million, twenty-one thousand, nine hundred sixty-nine".