21418172 has 6 divisors (see below), whose sum is σ = 37481808. Its totient is φ = 10709084.

The previous prime is 21418157. The next prime is 21418183. The reversal of 21418172 is 27181412.

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, 2677268 + ... + 2677275.

It is an arithmetic number, because the mean of its divisors is an integer number (6246968).

Almost surely, 2^21418172 is an apocalyptic number.

It is an amenable number.

21418172 is a deficient number, since it is larger than the sum of its proper divisors (16063636).

21418172 is a wasteful number, since it uses less digits than its factorization.

21418172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5354547 (or 5354545 counting only the distinct ones).

The product of its digits is 896, while the sum is 26.

The square root of 21418172 is about 4627.9770958811. The cubic root of 21418172 is about 277.7116724948.

Adding to 21418172 its reverse (27181412), we get a palindrome (48599584).

The spelling of 21418172 in words is "twenty-one million, four hundred eighteen thousand, one hundred seventy-two".