21651176641 has 2 divisors, whose sum is σ = 21651176642. Its totient is φ = 21651176640.

The previous prime is 21651176627. The next prime is 21651176683. The reversal of 21651176641 is 14667115612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21549065616 + 102111025 = 146796^2 + 10105^2 .

It is a cyclic number.

It is not a de Polignac number, because 21651176641 - 2⁷ = 21651176513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21651176594 and 21651176603.

It is not a weakly prime, because it can be changed into another prime (21651176611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825588320 + 10825588321.

It is an arithmetic number, because the mean of its divisors is an integer number (10825588321).

Almost surely, 2^21651176641 is an apocalyptic number.

It is an amenable number.

21651176641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21651176641 is an equidigital number, since it uses as much as digits as its factorization.

21651176641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 40.

The spelling of 21651176641 in words is "twenty-one billion, six hundred fifty-one million, one hundred seventy-six thousand, six hundred forty-one".