20926681 has 4 divisors (see below), whose sum is σ = 21413392. Its totient is φ = 20439972.

The previous prime is 20926669. The next prime is 20926699. The reversal of 20926681 is 18662902.

It is a happy number.

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 20926681 - 2⁷ = 20926553 is a prime.

It is a super-2 number, since 2×20926681² = 875851955351522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20926621) 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, 243291 + ... + 243376.

It is an arithmetic number, because the mean of its divisors is an integer number (5353348).

Almost surely, 2^20926681 is an apocalyptic number.

It is an amenable number.

20926681 is a deficient number, since it is larger than the sum of its proper divisors (486711).

20926681 is an equidigital number, since it uses as much as digits as its factorization.

20926681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486710.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 20926681 is about 4574.5689414414. The cubic root of 20926681 is about 275.5709613947.

The spelling of 20926681 in words is "twenty million, nine hundred twenty-six thousand, six hundred eighty-one".