215064661 has 4 divisors (see below), whose sum is σ = 245788192. Its totient is φ = 184341132.

The previous prime is 215064659. The next prime is 215064677. The reversal of 215064661 is 166460512.

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 215064661 - 2¹ = 215064659 is a prime.

It is a super-2 number, since 2×215064661² = 92505616822089842, which 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 (215064611) 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, 15361755 + ... + 15361768.

It is an arithmetic number, because the mean of its divisors is an integer number (61447048).

Almost surely, 2^215064661 is an apocalyptic number.

It is an amenable number.

215064661 is a deficient number, since it is larger than the sum of its proper divisors (30723531).

215064661 is an equidigital number, since it uses as much as digits as its factorization.

215064661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30723530.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 215064661 is about 14665.0830546574. The cubic root of 215064661 is about 599.1326922700.

The spelling of 215064661 in words is "two hundred fifteen million, sixty-four thousand, six hundred sixty-one".