21897738 has 24 divisors (see below), whose sum is σ = 47981700. Its totient is φ = 7216704.

The previous prime is 21897703. The next prime is 21897763. The reversal of 21897738 is 83779812.

It can be written as a sum of positive squares in 2 ways, for example, as 21874329 + 23409 = 4677^2 + 153^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21897693 and 21897702.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5233 + ... + 8436.

Almost surely, 2^21897738 is an apocalyptic number.

21897738 is an abundant number, since it is smaller than the sum of its proper divisors (26083962).

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

21897738 is a wasteful number, since it uses less digits than its factorization.

21897738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13766 (or 13763 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 21897738 is about 4679.5018965698. The cubic root of 21897738 is about 279.7691038664.

The spelling of 21897738 in words is "twenty-one million, eight hundred ninety-seven thousand, seven hundred thirty-eight".