215302681 has 6 divisors (see below), whose sum is σ = 236655146. Its totient is φ = 195729600.

The previous prime is 215302673. The next prime is 215302693. The reversal of 215302681 is 186203512.

It can be written as a sum of positive squares in only one way, i.e., 134931456 + 80371225 = 11616^2 + 8965^2 .

It is not a de Polignac number, because 215302681 - 2³ = 215302673 is a prime.

It is a super-2 number, since 2×215302681² = 92710488891575522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215302621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 889560 + ... + 889801.

Almost surely, 2^215302681 is an apocalyptic number.

It is an amenable number.

215302681 is a deficient number, since it is larger than the sum of its proper divisors (21352465).

215302681 is a wasteful number, since it uses less digits than its factorization.

215302681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1779383 (or 1779372 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 215302681 is about 14673.1960049609. The cubic root of 215302681 is about 599.3536382033.

The spelling of 215302681 in words is "two hundred fifteen million, three hundred two thousand, six hundred eighty-one".