21201738 has 16 divisors (see below), whose sum is σ = 42780096. Its totient is φ = 7004480.

The previous prime is 21201721. The next prime is 21201743. The reversal of 21201738 is 83710212.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14958 + ... + 16313.

It is an arithmetic number, because the mean of its divisors is an integer number (2673756).

Almost surely, 2^21201738 is an apocalyptic number.

21201738 is an abundant number, since it is smaller than the sum of its proper divisors (21578358).

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

21201738 is a wasteful number, since it uses less digits than its factorization.

21201738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31389.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21201738 is about 4604.5345041600. The cubic root of 21201738 is about 276.7730637052.

The spelling of 21201738 in words is "twenty-one million, two hundred one thousand, seven hundred thirty-eight".