21403420 has 12 divisors (see below), whose sum is σ = 44947224. Its totient is φ = 8561360.

The previous prime is 21403399. The next prime is 21403433. The reversal of 21403420 is 2430412.

It is a junction number, because it is equal to n+sod(n) for n = 21403394 and 21403403.

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, 535066 + ... + 535105.

It is an arithmetic number, because the mean of its divisors is an integer number (3745602).

Almost surely, 2^21403420 is an apocalyptic number.

21403420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21403420 is an abundant number, since it is smaller than the sum of its proper divisors (23543804).

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

21403420 is a wasteful number, since it uses less digits than its factorization.

21403420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1070180 (or 1070178 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21403420 is about 4626.3830364552. The cubic root of 21403420 is about 277.6478988679.

Adding to 21403420 its reverse (2430412), we get a palindrome (23833832).

The spelling of 21403420 in words is "twenty-one million, four hundred three thousand, four hundred twenty".