21002241457 has 2 divisors, whose sum is σ = 21002241458. Its totient is φ = 21002241456.

The previous prime is 21002241427. The next prime is 21002241461. The reversal of 21002241457 is 75414220012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19566134641 + 1436106816 = 139879^2 + 37896^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002241457 - 2²³ = 20993852849 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002241427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501120728 + 10501120729.

It is an arithmetic number, because the mean of its divisors is an integer number (10501120729).

Almost surely, 2^21002241457 is an apocalyptic number.

It is an amenable number.

21002241457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002241457 is an equidigital number, since it uses as much as digits as its factorization.

21002241457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 28.

Adding to 21002241457 its reverse (75414220012), we get a palindrome (96416461469).

The spelling of 21002241457 in words is "twenty-one billion, two million, two hundred forty-one thousand, four hundred fifty-seven".