21453631472989 has 2 divisors, whose sum is σ = 21453631472990. Its totient is φ = 21453631472988.

The previous prime is 21453631472983. The next prime is 21453631473037. The reversal of 21453631472989 is 98927413635412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21407370776100 + 46260696889 = 4626810^2 + 215083^2 .

It is a cyclic number.

It is not a de Polignac number, because 21453631472989 - 2¹⁷ = 21453631341917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21453631472989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21453631472983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726815736494 + 10726815736495.

It is an arithmetic number, because the mean of its divisors is an integer number (10726815736495).

Almost surely, 2^{21453631472989} is an apocalyptic number.

It is an amenable number.

21453631472989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21453631472989 is an equidigital number, since it uses as much as digits as its factorization.

21453631472989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 78382080, while the sum is 64.

The spelling of 21453631472989 in words is "twenty-one trillion, four hundred fifty-three billion, six hundred thirty-one million, four hundred seventy-two thousand, nine hundred eighty-nine".