21438902 has 4 divisors (see below), whose sum is σ = 32158356. Its totient is φ = 10719450.

The previous prime is 21438881. The next prime is 21438913. The reversal of 21438902 is 20983412.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5359724 + ... + 5359727.

It is an arithmetic number, because the mean of its divisors is an integer number (8039589).

Almost surely, 2^21438902 is an apocalyptic number.

21438902 is a deficient number, since it is larger than the sum of its proper divisors (10719454).

21438902 is a wasteful number, since it uses less digits than its factorization.

21438902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10719453.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21438902 is about 4630.2161936566. The cubic root of 21438902 is about 277.8012398434.

The spelling of 21438902 in words is "twenty-one million, four hundred thirty-eight thousand, nine hundred two".