653681 has 4 divisors (see below), whose sum is σ = 747072. Its totient is φ = 560292.

The previous prime is 653659. The next prime is 653687. The reversal of 653681 is 186356.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 653681 - 2⁶ = 653617 is a prime.

It is a super-2 number, since 2×653681² = 854597699522, which contains 22 as substring.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 653681.

It is not an unprimeable number, because it can be changed into a prime (653687) 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, 46685 + ... + 46698.

It is an arithmetic number, because the mean of its divisors is an integer number (186768).

2⁶⁵³⁶⁸¹ is an apocalyptic number.

It is an amenable number.

653681 is a deficient number, since it is larger than the sum of its proper divisors (93391).

653681 is an equidigital number, since it uses as much as digits as its factorization.

653681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93390.

The product of its digits is 4320, while the sum is 29.

The square root of 653681 is about 808.5054112373. The cubic root of 653681 is about 86.7871221170.

The spelling of 653681 in words is "six hundred fifty-three thousand, six hundred eighty-one".