252606021681 has 16 divisors (see below), whose sum is σ = 362749721600. Its totient is φ = 155435552640.

The previous prime is 252606021677. The next prime is 252606021713. The reversal of 252606021681 is 186120606252.

It is not a de Polignac number, because 252606021681 - 2² = 252606021677 is a prime.

It is a super-2 number, since 2×252606021681² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (252606021671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139245 + ... + 724293.

It is an arithmetic number, because the mean of its divisors is an integer number (22671857600).

Almost surely, 2^252606021681 is an apocalyptic number.

It is an amenable number.

252606021681 is a deficient number, since it is larger than the sum of its proper divisors (110143699919).

252606021681 is a wasteful number, since it uses less digits than its factorization.

252606021681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596136.

The product of its (nonzero) digits is 69120, while the sum is 39.

The spelling of 252606021681 in words is "two hundred fifty-two billion, six hundred six million, twenty-one thousand, six hundred eighty-one".