21418938 has 16 divisors (see below), whose sum is σ = 47597760. Its totient is φ = 7139628.

The previous prime is 21418937. The next prime is 21418951. The reversal of 21418938 is 83981412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418937) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 198270 + ... + 198377.

It is an arithmetic number, because the mean of its divisors is an integer number (2974860).

Almost surely, 2^21418938 is an apocalyptic number.

21418938 is an abundant number, since it is smaller than the sum of its proper divisors (26178822).

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

21418938 is a wasteful number, since it uses less digits than its factorization.

21418938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396658 (or 396652 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21418938 is about 4628.0598526813. The cubic root of 21418938 is about 277.7149831509.

The spelling of 21418938 in words is "twenty-one million, four hundred eighteen thousand, nine hundred thirty-eight".