215164240 has 40 divisors (see below), whose sum is σ = 529687080. Its totient is φ = 81002496.

The previous prime is 215164237. The next prime is 215164249. The reversal of 215164240 is 42461512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 14318656 + 200845584 = 3784^2 + 14172^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215164249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77745 + ... + 80464.

It is an arithmetic number, because the mean of its divisors is an integer number (13242177).

Almost surely, 2^215164240 is an apocalyptic number.

215164240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215164240 is an abundant number, since it is smaller than the sum of its proper divisors (314522840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

215164240 is a wasteful number, since it uses less digits than its factorization.

215164240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158239 (or 158233 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 215164240 is about 14668.4777669668. The cubic root of 215164240 is about 599.2251479193.

The spelling of 215164240 in words is "two hundred fifteen million, one hundred sixty-four thousand, two hundred forty".