21890403 has 6 divisors (see below), whose sum is σ = 31619484. Its totient is φ = 14593596.

The previous prime is 21890383. The next prime is 21890417. The reversal of 21890403 is 30409812.

It is not a de Polignac number, because 21890403 - 2²⁴ = 5113187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21890423) 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 5 ways as a sum of consecutive naturals, for example, 1216125 + ... + 1216142.

It is an arithmetic number, because the mean of its divisors is an integer number (5269914).

Almost surely, 2^21890403 is an apocalyptic number.

21890403 is a deficient number, since it is larger than the sum of its proper divisors (9729081).

21890403 is a wasteful number, since it uses less digits than its factorization.

21890403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2432273 (or 2432270 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21890403 is about 4678.7180936663. The cubic root of 21890403 is about 279.7378626555.

The spelling of 21890403 in words is "twenty-one million, eight hundred ninety thousand, four hundred three".