21712182977 has 2 divisors, whose sum is σ = 21712182978. Its totient is φ = 21712182976.

The previous prime is 21712182887. The next prime is 21712182983. The reversal of 21712182977 is 77928121712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20460155521 + 1252027456 = 143039^2 + 35384^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21712182977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21712182377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856091488 + 10856091489.

It is an arithmetic number, because the mean of its divisors is an integer number (10856091489).

Almost surely, 2^21712182977 is an apocalyptic number.

It is an amenable number.

21712182977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21712182977 is an equidigital number, since it uses as much as digits as its factorization.

21712182977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 197568, while the sum is 47.

The spelling of 21712182977 in words is "twenty-one billion, seven hundred twelve million, one hundred eighty-two thousand, nine hundred seventy-seven".