21999999977 has 2 divisors, whose sum is σ = 21999999978. Its totient is φ = 21999999976.

The previous prime is 21999999971. The next prime is 22000000007. The reversal of 21999999977 is 77999999912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16549278736 + 5450721241 = 128644^2 + 73829^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21999999977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21999999971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10999999988 + 10999999989.

It is an arithmetic number, because the mean of its divisors is an integer number (10999999989).

Almost surely, 2^21999999977 is an apocalyptic number.

It is an amenable number.

21999999977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21999999977 is an equidigital number, since it uses as much as digits as its factorization.

21999999977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 468730962, while the sum is 80.

The spelling of 21999999977 in words is "twenty-one billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred seventy-seven".