2635681 has 4 divisors (see below), whose sum is σ = 2639152. Its totient is φ = 2632212.

The previous prime is 2635673. The next prime is 2635691. The reversal of 2635681 is 1865362.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1865362 = 2 ⋅932681.

It is a cyclic number.

It is not a de Polignac number, because 2635681 - 2³ = 2635673 is a prime.

It is a super-2 number, since 2×2635681² = 13893628667522, which contains 22 as substring.

It is a Duffinian number.

2635681 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2635691) 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, 51 + ... + 2296.

It is an arithmetic number, because the mean of its divisors is an integer number (659788).

2^2635681 is an apocalyptic number.

It is an amenable number.

2635681 is a deficient number, since it is larger than the sum of its proper divisors (3471).

2635681 is a wasteful number, since it uses less digits than its factorization.

2635681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3470.

The product of its digits is 8640, while the sum is 31.

The square root of 2635681 is about 1623.4780565194. The cubic root of 2635681 is about 138.1330544773.

The spelling of 2635681 in words is "two million, six hundred thirty-five thousand, six hundred eighty-one".