20926821 has 8 divisors (see below), whose sum is σ = 27923584. Its totient is φ = 13940640.

The previous prime is 20926817. The next prime is 20926831. The reversal of 20926821 is 12862902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20926821 - 2² = 20926817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20926811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6180 + ... + 8946.

It is an arithmetic number, because the mean of its divisors is an integer number (3490448).

Almost surely, 2^20926821 is an apocalyptic number.

It is an amenable number.

20926821 is a deficient number, since it is larger than the sum of its proper divisors (6996763).

20926821 is a wasteful number, since it uses less digits than its factorization.

20926821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5291.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20926821 is about 4574.5842434040. The cubic root of 20926821 is about 275.5715759187.

It can be divided in two parts, 20 and 926821, that added together give a triangular number (926841 = T₁₃₆₁).

The spelling of 20926821 in words is "twenty million, nine hundred twenty-six thousand, eight hundred twenty-one".