21942903 has 12 divisors (see below), whose sum is σ = 31080680. Its totient is φ = 13767552.

The previous prime is 21942889. The next prime is 21942911. The reversal of 21942903 is 30924912.

It is not a de Polignac number, because 21942903 - 2⁵ = 21942871 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21942923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11788 + ... + 13521.

Almost surely, 2^21942903 is an apocalyptic number.

21942903 is a deficient number, since it is larger than the sum of its proper divisors (9137777).

21942903 is a wasteful number, since it uses less digits than its factorization.

21942903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25346 (or 25329 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 21942903 is about 4684.3252448992. The cubic root of 21942903 is about 279.9613169349.

Subtracting 21942903 from its reverse (30924912), we obtain a square (8982009 = 2997²).

The spelling of 21942903 in words is "twenty-one million, nine hundred forty-two thousand, nine hundred three".