21538342 has 16 divisors (see below), whose sum is σ = 37677600. Its totient is φ = 9230424.

The previous prime is 21538339. The next prime is 21538379. The reversal of 21538342 is 24383512.

It is a super-2 number, since 2×21538342² = 927800352217928, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21538342.

It is a congruent 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, 15013 + ... + 16384.

It is an arithmetic number, because the mean of its divisors is an integer number (2354850).

Almost surely, 2^21538342 is an apocalyptic number.

21538342 is a deficient number, since it is larger than the sum of its proper divisors (16139258).

21538342 is an equidigital number, since it uses as much as digits as its factorization.

21538342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31420 (or 31406 counting only the distinct ones).

The product of its digits is 5760, while the sum is 28.

The square root of 21538342 is about 4640.9419302551. The cubic root of 21538342 is about 278.2300857285.

The spelling of 21538342 in words is "twenty-one million, five hundred thirty-eight thousand, three hundred forty-two".