21999830557 has 2 divisors, whose sum is σ = 21999830558. Its totient is φ = 21999830556.

The previous prime is 21999830549. The next prime is 21999830617. The reversal of 21999830557 is 75503899912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16427805241 + 5572025316 = 128171^2 + 74646^2 .

It is a cyclic number.

It is not a de Polignac number, because 21999830557 - 2³ = 21999830549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21999830507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10999915278 + 10999915279.

It is an arithmetic number, because the mean of its divisors is an integer number (10999915279).

Almost surely, 2^21999830557 is an apocalyptic number.

It is an amenable number.

21999830557 is a deficient number, since it is larger than the sum of its proper divisors (1).

21999830557 is an equidigital number, since it uses as much as digits as its factorization.

21999830557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6123600, while the sum is 58.

The spelling of 21999830557 in words is "twenty-one billion, nine hundred ninety-nine million, eight hundred thirty thousand, five hundred fifty-seven".