215461561 has 16 divisors (see below), whose sum is σ = 256112640. Its totient is φ = 177347520.

The previous prime is 215461529. The next prime is 215461567. The reversal of 215461561 is 165164512.

It is not a de Polignac number, because 215461561 - 2⁵ = 215461529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215461567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35995 + ... + 41551.

It is an arithmetic number, because the mean of its divisors is an integer number (16007040).

Almost surely, 2^215461561 is an apocalyptic number.

It is an amenable number.

215461561 is a deficient number, since it is larger than the sum of its proper divisors (40651079).

215461561 is a wasteful number, since it uses less digits than its factorization.

215461561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5784.

The product of its digits is 7200, while the sum is 31.

The square root of 215461561 is about 14678.6089599798. The cubic root of 215461561 is about 599.5010305345.

The spelling of 215461561 in words is "two hundred fifteen million, four hundred sixty-one thousand, five hundred sixty-one".