21830840 has 32 divisors (see below), whose sum is σ = 49410000. Its totient is φ = 8680704.

The previous prime is 21830803. The next prime is 21830843. The reversal of 21830840 is 4803812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21830843) 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, 5636 + ... + 8684.

Almost surely, 2^21830840 is an apocalyptic number.

21830840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21830840 is an abundant number, since it is smaller than the sum of its proper divisors (27579160).

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

21830840 is a wasteful number, since it uses less digits than its factorization.

21830840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3239 (or 3235 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21830840 is about 4672.3484459103. The cubic root of 21830840 is about 279.4839132961.

The spelling of 21830840 in words is "twenty-one million, eight hundred thirty thousand, eight hundred forty".