21920738 has 12 divisors (see below), whose sum is σ = 38249622. Its totient is φ = 9394560.

The previous prime is 21920711. The next prime is 21920741. The reversal of 21920738 is 83702912.

It can be written as a sum of positive squares in only one way, i.e., 20133169 + 1787569 = 4487^2 + 1337^2 .

It is a Curzon 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, 111743 + ... + 111938.

Almost surely, 2^21920738 is an apocalyptic number.

21920738 is a deficient number, since it is larger than the sum of its proper divisors (16328884).

21920738 is a wasteful number, since it uses less digits than its factorization.

21920738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223697 (or 223690 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21920738 is about 4681.9587781184. The cubic root of 21920738 is about 279.8670201875.

The spelling of 21920738 in words is "twenty-one million, nine hundred twenty thousand, seven hundred thirty-eight".