21651767411779 has 2 divisors, whose sum is σ = 21651767411780. Its totient is φ = 21651767411778.

The previous prime is 21651767411753. The next prime is 21651767411801. The reversal of 21651767411779 is 97711476715612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21651767411779 - 2¹³ = 21651767403587 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21651767411779.

It is not a weakly prime, because it can be changed into another prime (21651767411749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825883705889 + 10825883705890.

It is an arithmetic number, because the mean of its divisors is an integer number (10825883705890).

Almost surely, 2^{21651767411779} is an apocalyptic number.

21651767411779 is a deficient number, since it is larger than the sum of its proper divisors (1).

21651767411779 is an equidigital number, since it uses as much as digits as its factorization.

21651767411779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31116960, while the sum is 64.

The spelling of 21651767411779 in words is "twenty-one trillion, six hundred fifty-one billion, seven hundred sixty-seven million, four hundred eleven thousand, seven hundred seventy-nine".