21738492 has 18 divisors (see below), whose sum is σ = 54950168. Its totient is φ = 7246152.

The previous prime is 21738481. The next prime is 21738503. The reversal of 21738492 is 29483712.

It is an interprime number because it is at equal distance from previous prime (21738481) and next prime (21738503).

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 603847 = 21738492 / (2 + 1 + 7 + 3 + 8 + 4 + 9 + 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 301888 + ... + 301959.

Almost surely, 2^21738492 is an apocalyptic number.

It is an amenable number.

21738492 is an abundant number, since it is smaller than the sum of its proper divisors (33211676).

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

21738492 is a wasteful number, since it uses less digits than its factorization.

21738492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603857 (or 603852 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21738492 is about 4662.4555761959. The cubic root of 21738492 is about 279.0892688484.

The spelling of 21738492 in words is "twenty-one million, seven hundred thirty-eight thousand, four hundred ninety-two".