2157382252809 has 81 divisors (see below), whose sum is σ = 3790696515879. Its totient is φ = 1178802535680.

The previous prime is 2157382252799. The next prime is 2157382252847. The reversal of 2157382252809 is 9082522837512.

The square root of 2157382252809 is 1468803.

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

2157382252809 is a `hidden beast` number, since 2 + 1 + 5 + 7 + 382 + 252 + 8 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2112217502409 + 45164750400 = 1453347^2 + 212520^2 .

It is not a de Polignac number, because 2157382252809 - 2²⁵ = 2157348698377 is a prime.

It is a super-3 number, since 3×2157382252809³ (a number of 38 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2157382250809) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 709430329 + ... + 709433369.

Almost surely, 2^{2157382252809} is an apocalyptic number.

2157382252809 is the 1468803-rd square number.

2157382252809 is the 734402-nd centered octagonal number.

It is an amenable number.

2157382252809 is a deficient number, since it is larger than the sum of its proper divisors (1633314263070).

2157382252809 is an frugal number, since it uses more digits than its factorization.

2157382252809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6148 (or 3074 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 2157382252809 in words is "two trillion, one hundred fifty-seven billion, three hundred eighty-two million, two hundred fifty-two thousand, eight hundred nine".