16540857325621 has 4 divisors (see below), whose sum is σ = 16540891073644. Its totient is φ = 16540823577600.

The previous prime is 16540857325571. The next prime is 16540857325633. The reversal of 16540857325621 is 12652375804561.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10441493568900 + 6099363756721 = 3231330^2 + 2469689^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16540857325621 is a prime.

It is a super-2 number, since 2×16540857325621² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16540857385621) 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, 16127820 + ... + 17122741.

It is an arithmetic number, because the mean of its divisors is an integer number (4135222768411).

Almost surely, 2^{16540857325621} is an apocalyptic number.

It is an amenable number.

16540857325621 is a deficient number, since it is larger than the sum of its proper divisors (33748023).

16540857325621 is an equidigital number, since it uses as much as digits as its factorization.

16540857325621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33748022.

The product of its (nonzero) digits is 12096000, while the sum is 55.

The spelling of 16540857325621 in words is "sixteen trillion, five hundred forty billion, eight hundred fifty-seven million, three hundred twenty-five thousand, six hundred twenty-one".