63216581 has 4 divisors (see below), whose sum is σ = 65965152. Its totient is φ = 60468012.

The previous prime is 63216541. The next prime is 63216583. The reversal of 63216581 is 18561236.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 63216581 - 2¹⁰ = 63215557 is a prime.

It is a super-2 number, since 2×63216581² = 7992672226659122, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63216583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1374251 + ... + 1374296.

It is an arithmetic number, because the mean of its divisors is an integer number (16491288).

Almost surely, 2^63216581 is an apocalyptic number.

It is an amenable number.

63216581 is a deficient number, since it is larger than the sum of its proper divisors (2748571).

63216581 is a wasteful number, since it uses less digits than its factorization.

63216581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2748570.

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

The square root of 63216581 is about 7950.8855481638. The cubic root of 63216581 is about 398.3611718589.

The spelling of 63216581 in words is "sixty-three million, two hundred sixteen thousand, five hundred eighty-one".