215691138026329 has 15 divisors (see below), whose sum is σ = 251625528244853. Its totient is φ = 184877501478348.

The previous prime is 215691138026327. The next prime is 215691138026411. The reversal of 215691138026329 is 923620831196512.

It is a happy number.

The square root of 215691138026329 is 14686427.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 215691138026329 - 2¹ = 215691138026327 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215691138026327) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 719485062 + ... + 719784784.

Almost surely, 2^{215691138026329} is an apocalyptic number.

215691138026329 is the 14686427-th square number.

215691138026329 is the 7343214-th centered octagonal number.

It is an amenable number.

215691138026329 is a deficient number, since it is larger than the sum of its proper divisors (35934390218524).

215691138026329 is an frugal number, since it uses more digits than its factorization.

215691138026329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599474 (or 299730 counting only the distinct ones).

The product of its (nonzero) digits is 8398080, while the sum is 58.

The spelling of 215691138026329 in words is "two hundred fifteen trillion, six hundred ninety-one billion, one hundred thirty-eight million, twenty-six thousand, three hundred twenty-nine".