21726442 has 12 divisors (see below), whose sum is σ = 34620390. Its totient is φ = 10223936.

The previous prime is 21726427. The next prime is 21726461. The reversal of 21726442 is 24462712.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 21724921 + 1521 = 4661^2 + 39^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21726442.

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, 18217 + ... + 19372.

Almost surely, 2^21726442 is an apocalyptic number.

21726442 is a deficient number, since it is larger than the sum of its proper divisors (12893948).

21726442 is a wasteful number, since it uses less digits than its factorization.

21726442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37625 (or 37608 counting only the distinct ones).

The product of its digits is 5376, while the sum is 28.

The square root of 21726442 is about 4661.1631595558. The cubic root of 21726442 is about 279.0376914088.

The spelling of 21726442 in words is "twenty-one million, seven hundred twenty-six thousand, four hundred forty-two".