21151224354649 has 2 divisors, whose sum is σ = 21151224354650. Its totient is φ = 21151224354648.

The previous prime is 21151224354587. The next prime is 21151224354671. The reversal of 21151224354649 is 94645342215112.

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., 20907820265049 + 243404089600 = 4572507^2 + 493360^2 .

It is a cyclic number.

It is not a de Polignac number, because 21151224354649 - 2²¹ = 21151222257497 is a prime.

It is not a weakly prime, because it can be changed into another prime (21151224354679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10575612177324 + 10575612177325.

It is an arithmetic number, because the mean of its divisors is an integer number (10575612177325).

Almost surely, 2^{21151224354649} is an apocalyptic number.

It is an amenable number.

21151224354649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21151224354649 is an equidigital number, since it uses as much as digits as its factorization.

21151224354649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2073600, while the sum is 49.

The spelling of 21151224354649 in words is "twenty-one trillion, one hundred fifty-one billion, two hundred twenty-four million, three hundred fifty-four thousand, six hundred forty-nine".