21340920 has 32 divisors (see below), whose sum is σ = 64023120. Its totient is φ = 5690880.

The previous prime is 21340889. The next prime is 21340931. The reversal of 21340920 is 2904312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88801 + ... + 89040.

Almost surely, 2^21340920 is an apocalyptic number.

21340920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21340920 is an abundant number, since it is smaller than the sum of its proper divisors (42682200).

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

21340920 is a wasteful number, since it uses less digits than its factorization.

21340920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177855 (or 177851 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21340920 is about 4619.6233612709. The cubic root of 21340920 is about 277.3773827242.

The spelling of 21340920 in words is "twenty-one million, three hundred forty thousand, nine hundred twenty".