216525137 has 4 divisors (see below), whose sum is σ = 217904436. Its totient is φ = 215145840.

The previous prime is 216525131. The next prime is 216525143. The reversal of 216525137 is 731525612.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (216525131) and next prime (216525143).

It can be written as a sum of positive squares in 2 ways, for example, as 104673361 + 111851776 = 10231^2 + 10576^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216525137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216525131) 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, 689414 + ... + 689727.

It is an arithmetic number, because the mean of its divisors is an integer number (54476109).

Almost surely, 2^216525137 is an apocalyptic number.

It is an amenable number.

216525137 is a deficient number, since it is larger than the sum of its proper divisors (1379299).

216525137 is a wasteful number, since it uses less digits than its factorization.

216525137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1379298.

The product of its digits is 12600, while the sum is 32.

The square root of 216525137 is about 14714.7931348015. The cubic root of 216525137 is about 600.4858444487.

The spelling of 216525137 in words is "two hundred sixteen million, five hundred twenty-five thousand, one hundred thirty-seven".