21662552461549 has 2 divisors, whose sum is σ = 21662552461550. Its totient is φ = 21662552461548.

The previous prime is 21662552461457. The next prime is 21662552461553. The reversal of 21662552461549 is 94516425526612.

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., 15892381575625 + 5770170885924 = 3986525^2 + 2402118^2 .

It is a cyclic number.

It is not a de Polignac number, because 21662552461549 - 2³¹ = 21660404977901 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21662552461493 and 21662552461502.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21662552464549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10831276230774 + 10831276230775.

It is an arithmetic number, because the mean of its divisors is an integer number (10831276230775).

Almost surely, 2^{21662552461549} is an apocalyptic number.

It is an amenable number.

21662552461549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21662552461549 is an equidigital number, since it uses as much as digits as its factorization.

21662552461549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104000, while the sum is 58.

The spelling of 21662552461549 in words is "twenty-one trillion, six hundred sixty-two billion, five hundred fifty-two million, four hundred sixty-one thousand, five hundred forty-nine".