21777570641 has 2 divisors, whose sum is σ = 21777570642. Its totient is φ = 21777570640.

The previous prime is 21777570583. The next prime is 21777570643. The reversal of 21777570641 is 14607577712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19492348225 + 2285222416 = 139615^2 + 47804^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21777570641 is a prime.

Together with 21777570643, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21777570643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10888785320 + 10888785321.

It is an arithmetic number, because the mean of its divisors is an integer number (10888785321).

Almost surely, 2^21777570641 is an apocalyptic number.

It is an amenable number.

21777570641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21777570641 is an equidigital number, since it uses as much as digits as its factorization.

21777570641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576240, while the sum is 47.

The spelling of 21777570641 in words is "twenty-one billion, seven hundred seventy-seven million, five hundred seventy thousand, six hundred forty-one".