216952617581 has 4 divisors (see below), whose sum is σ = 247945848672. Its totient is φ = 185959386492.

The previous prime is 216952617571. The next prime is 216952617587. The reversal of 216952617581 is 185716259612.

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 a cyclic number.

It is not a de Polignac number, because 216952617581 - 2¹⁴ = 216952601197 is a prime.

It is a super-2 number, since 2×216952617581² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216952617587) 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, 15496615535 + ... + 15496615548.

It is an arithmetic number, because the mean of its divisors is an integer number (61986462168).

Almost surely, 2^216952617581 is an apocalyptic number.

It is an amenable number.

216952617581 is a deficient number, since it is larger than the sum of its proper divisors (30993231091).

216952617581 is an equidigital number, since it uses as much as digits as its factorization.

216952617581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30993231090.

The product of its digits is 1814400, while the sum is 53.

The spelling of 216952617581 in words is "two hundred sixteen billion, nine hundred fifty-two million, six hundred seventeen thousand, five hundred eighty-one".