215798661 has 40 divisors (see below), whose sum is σ = 349099520. Its totient is φ = 132059808.

The previous prime is 215798659. The next prime is 215798707. The reversal of 215798661 is 166897512.

It is not a de Polignac number, because 215798661 - 2¹ = 215798659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215798651) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 234360 + ... + 235278.

It is an arithmetic number, because the mean of its divisors is an integer number (8727488).

Almost surely, 2^215798661 is an apocalyptic number.

It is an amenable number.

215798661 is a deficient number, since it is larger than the sum of its proper divisors (133300859).

215798661 is a wasteful number, since it uses less digits than its factorization.

215798661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1167 (or 1158 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 215798661 is about 14690.0871678830. The cubic root of 215798661 is about 599.8135170462.

The spelling of 215798661 in words is "two hundred fifteen million, seven hundred ninety-eight thousand, six hundred sixty-one".