653173981 has 4 divisors (see below), whose sum is σ = 655715772. Its totient is φ = 650632192.

The previous prime is 653173979. The next prime is 653174029. The reversal of 653173981 is 189371356.

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 630763225 + 22410756 = 25115^2 + 4734^2 .

It is a cyclic number.

It is not a de Polignac number, because 653173981 - 2¹ = 653173979 is a prime.

It is a super-2 number, since 2×653173981² = 853272498910776722, which 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 (653173901) 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, 1270510 + ... + 1271023.

It is an arithmetic number, because the mean of its divisors is an integer number (163928943).

Almost surely, 2^653173981 is an apocalyptic number.

It is an amenable number.

653173981 is a deficient number, since it is larger than the sum of its proper divisors (2541791).

653173981 is a wasteful number, since it uses less digits than its factorization.

653173981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2541790.

The product of its digits is 136080, while the sum is 43.

The square root of 653173981 is about 25557.2686529684. The cubic root of 653173981 is about 867.6467788636.

The spelling of 653173981 in words is "six hundred fifty-three million, one hundred seventy-three thousand, nine hundred eighty-one".