21357872269 has 2 divisors, whose sum is σ = 21357872270. Its totient is φ = 21357872268.

The previous prime is 21357872231. The next prime is 21357872273. The reversal of 21357872269 is 96227875312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18560520169 + 2797352100 = 136237^2 + 52890^2 .

It is a cyclic number.

It is not a de Polignac number, because 21357872269 - 2¹⁵ = 21357839501 is a prime.

It is a super-2 number, since 2×21357872269² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21357872969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678936134 + 10678936135.

It is an arithmetic number, because the mean of its divisors is an integer number (10678936135).

Almost surely, 2^21357872269 is an apocalyptic number.

It is an amenable number.

21357872269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21357872269 is an equidigital number, since it uses as much as digits as its factorization.

21357872269 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2540160, while the sum is 52.

The spelling of 21357872269 in words is "twenty-one billion, three hundred fifty-seven million, eight hundred seventy-two thousand, two hundred sixty-nine".