21202840 has 32 divisors (see below), whose sum is σ = 47940480. Its totient is φ = 8439552.

The previous prime is 21202817. The next prime is 21202843. The reversal of 21202840 is 4820212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7732 + ... + 10108.

It is an arithmetic number, because the mean of its divisors is an integer number (1498140).

Almost surely, 2^21202840 is an apocalyptic number.

21202840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202840 is an abundant number, since it is smaller than the sum of its proper divisors (26737640).

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

21202840 is a wasteful number, since it uses less digits than its factorization.

21202840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2611 (or 2607 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 21202840 is about 4604.6541672530. The cubic root of 21202840 is about 276.7778588881. Note that the first 3 decimals are identical.

The spelling of 21202840 in words is "twenty-one million, two hundred two thousand, eight hundred forty".