63215681 has 2 divisors, whose sum is σ = 63215682. Its totient is φ = 63215680.

The previous prime is 63215651. The next prime is 63215687. The reversal of 63215681 is 18651236.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57532225 + 5683456 = 7585^2 + 2384^2 .

It is a cyclic number.

It is not a de Polignac number, because 63215681 - 2⁶ = 63215617 is a prime.

It is a super-2 number, since 2×63215681² = 7992444648587522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (63215687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31607840 + 31607841.

It is an arithmetic number, because the mean of its divisors is an integer number (31607841).

Almost surely, 2^63215681 is an apocalyptic number.

It is an amenable number.

63215681 is a deficient number, since it is larger than the sum of its proper divisors (1).

63215681 is an equidigital number, since it uses as much as digits as its factorization.

63215681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 32.

The square root of 63215681 is about 7950.8289504931. The cubic root of 63215681 is about 398.3592813910.

The spelling of 63215681 in words is "sixty-three million, two hundred fifteen thousand, six hundred eighty-one".