216513431 has 4 divisors (see below), whose sum is σ = 216568992. Its totient is φ = 216457872.

The previous prime is 216513419. The next prime is 216513433. The reversal of 216513431 is 134315612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216513431 is a prime.

It is a super-2 number, since 2×216513431² = 93756131606783522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216513431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216513433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21455 + ... + 29888.

It is an arithmetic number, because the mean of its divisors is an integer number (54142248).

Almost surely, 2^216513431 is an apocalyptic number.

216513431 is a deficient number, since it is larger than the sum of its proper divisors (55561).

216513431 is an equidigital number, since it uses as much as digits as its factorization.

216513431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55560.

The product of its digits is 2160, while the sum is 26.

The square root of 216513431 is about 14714.3953664430. The cubic root of 216513431 is about 600.4750228969.

The spelling of 216513431 in words is "two hundred sixteen million, five hundred thirteen thousand, four hundred thirty-one".