216564731 has 8 divisors (see below), whose sum is σ = 220871664. Its totient is φ = 212266080.

The previous prime is 216564713. The next prime is 216564773. The reversal of 216564731 is 137465612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216564731 - 2²² = 212370427 is a prime.

It is a super-2 number, since 2×216564731² = 93800565426204722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216564691 and 216564700.

It is not an unprimeable number, because it can be changed into a prime (216564781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91100 + ... + 93446.

It is an arithmetic number, because the mean of its divisors is an integer number (27608958).

Almost surely, 2^216564731 is an apocalyptic number.

216564731 is a deficient number, since it is larger than the sum of its proper divisors (4306933).

216564731 is a wasteful number, since it uses less digits than its factorization.

216564731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4141.

The product of its digits is 30240, while the sum is 35.

The square root of 216564731 is about 14716.1384540918. The cubic root of 216564731 is about 600.5224440291.

The spelling of 216564731 in words is "two hundred sixteen million, five hundred sixty-four thousand, seven hundred thirty-one".