21074840 has 16 divisors (see below), whose sum is σ = 47418480. Its totient is φ = 8429920.

The previous prime is 21074813. The next prime is 21074843. The reversal of 21074840 is 4847012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21074843) 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, 263396 + ... + 263475.

It is an arithmetic number, because the mean of its divisors is an integer number (2963655).

Almost surely, 2^21074840 is an apocalyptic number.

21074840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21074840 is an abundant number, since it is smaller than the sum of its proper divisors (26343640).

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

21074840 is a wasteful number, since it uses less digits than its factorization.

21074840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526882 (or 526878 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21074840 is about 4590.7341460816. The cubic root of 21074840 is about 276.2197717448.

The spelling of 21074840 in words is "twenty-one million, seventy-four thousand, eight hundred forty".