2158457550561 has 135 divisors (see below), whose sum is σ = 3624386899419. Its totient is φ = 1279516912128.

The previous prime is 2158457550539. The next prime is 2158457550637. The reversal of 2158457550561 is 1650557548512.

The square root of 2158457550561 is 1469169.

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

2158457550561 is a `hidden beast` number, since 2 + 1 + 5 + 8 + 4 + 5 + 75 + 5 + 0 + 561 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 2157135500961 + 1322049600 = 1468719^2 + 36360^2 .

It is not a de Polignac number, because 2158457550561 - 2⁹ = 2158457550049 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2158457550498 and 2158457550507.

It is not an unprimeable number, because it can be changed into a prime (2158457550521) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 4984890201 + ... + 4984890633.

Almost surely, 2^{2158457550561} is an apocalyptic number.

2158457550561 is the 1469169-th square number.

2158457550561 is the 734585-th centered octagonal number.

It is an amenable number.

2158457550561 is a deficient number, since it is larger than the sum of its proper divisors (1465929348858).

2158457550561 is an frugal number, since it uses more digits than its factorization.

2158457550561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 962 (or 478 counting only the distinct ones).

The product of its (nonzero) digits is 8400000, while the sum is 54.

The spelling of 2158457550561 in words is "two trillion, one hundred fifty-eight billion, four hundred fifty-seven million, five hundred fifty thousand, five hundred sixty-one".