615681 has 20 divisors (see below), whose sum is σ = 1004784. Its totient is φ = 372600.

The previous prime is 615679. The next prime is 615709. The reversal of 615681 is 186516.

It is not a de Polignac number, because 615681 - 2¹ = 615679 is a prime.

It is a super-2 number, since 2×615681² = 758126187522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 615681.

It is not an unprimeable number, because it can be changed into a prime (615661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 546 + ... + 1236.

2⁶¹⁵⁶⁸¹ is an apocalyptic number.

It is an amenable number.

615681 is a deficient number, since it is larger than the sum of its proper divisors (389103).

615681 is a wasteful number, since it uses less digits than its factorization.

615681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714 (or 705 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 615681 is about 784.6534266796. The cubic root of 615681 is about 85.0717272299.

It can be divided in two parts, 615 and 681, that added together give a 4-th power (1296 = 6⁴).

The spelling of 615681 in words is "six hundred fifteen thousand, six hundred eighty-one".