21393340 has 12 divisors (see below), whose sum is σ = 44926056. Its totient is φ = 8557328.

The previous prime is 21393313. The next prime is 21393367. The reversal of 21393340 is 4339312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21393313) and next prime (21393367).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 534814 + ... + 534853.

It is an arithmetic number, because the mean of its divisors is an integer number (3743838).

Almost surely, 2^21393340 is an apocalyptic number.

21393340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21393340 is an abundant number, since it is smaller than the sum of its proper divisors (23532716).

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

21393340 is a wasteful number, since it uses less digits than its factorization.

21393340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1069676 (or 1069674 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 25.

The square root of 21393340 is about 4625.2935042006. The cubic root of 21393340 is about 277.6043056745.

The spelling of 21393340 in words is "twenty-one million, three hundred ninety-three thousand, three hundred forty".