21213511590989 has 2 divisors, whose sum is σ = 21213511590990. Its totient is φ = 21213511590988.

The previous prime is 21213511590913. The next prime is 21213511591021. The reversal of 21213511590989 is 98909511531212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18451792758025 + 2761718832964 = 4295555^2 + 1661842^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213511590989 - 2¹² = 21213511586893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213517590989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606755795494 + 10606755795495.

It is an arithmetic number, because the mean of its divisors is an integer number (10606755795495).

Almost surely, 2^{21213511590989} is an apocalyptic number.

It is an amenable number.

21213511590989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213511590989 is an equidigital number, since it uses as much as digits as its factorization.

21213511590989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1749600, while the sum is 56.

The spelling of 21213511590989 in words is "twenty-one trillion, two hundred thirteen billion, five hundred eleven million, five hundred ninety thousand, nine hundred eighty-nine".