20821908 has 12 divisors (see below), whose sum is σ = 48584480. Its totient is φ = 6940632.

The previous prime is 20821907. The next prime is 20821909. The reversal of 20821908 is 80912802.

It is an interprime number because it is at equal distance from previous prime (20821907) and next prime (20821909).

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20821907) 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, 867568 + ... + 867591.

Almost surely, 2^20821908 is an apocalyptic number.

It is an amenable number.

20821908 is an abundant number, since it is smaller than the sum of its proper divisors (27762572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20821908 is a wasteful number, since it uses less digits than its factorization.

20821908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1735166 (or 1735164 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 20821908 is about 4563.1028916736. The cubic root of 20821908 is about 275.1102940505.

The spelling of 20821908 in words is "twenty million, eight hundred twenty-one thousand, nine hundred eight".