637480021 has 2 divisors, whose sum is σ = 637480022. Its totient is φ = 637480020.

The previous prime is 637480007. The next prime is 637480049. The reversal of 637480021 is 120084736.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 636300625 + 1179396 = 25225^2 + 1086^2 .

It is a cyclic number.

It is not a de Polignac number, because 637480021 - 2⁵ = 637479989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (637480721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318740010 + 318740011.

It is an arithmetic number, because the mean of its divisors is an integer number (318740011).

Almost surely, 2^637480021 is an apocalyptic number.

It is an amenable number.

637480021 is a deficient number, since it is larger than the sum of its proper divisors (1).

637480021 is an equidigital number, since it uses as much as digits as its factorization.

637480021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 637480021 is about 25248.3666996501. The cubic root of 637480021 is about 860.6413194548.

The spelling of 637480021 in words is "six hundred thirty-seven million, four hundred eighty thousand, twenty-one".