21758442 has 16 divisors (see below), whose sum is σ = 44693472. Its totient is φ = 7056720.

The previous prime is 21758431. The next prime is 21758449. The reversal of 21758442 is 24485712.

It is not an unprimeable number, because it can be changed into a prime (21758449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48784 + ... + 49227.

It is an arithmetic number, because the mean of its divisors is an integer number (2793342).

Almost surely, 2^21758442 is an apocalyptic number.

21758442 is an abundant number, since it is smaller than the sum of its proper divisors (22935030).

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

21758442 is a wasteful number, since it uses less digits than its factorization.

21758442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98053.

The product of its digits is 17920, while the sum is 33.

The square root of 21758442 is about 4664.5945161396. The cubic root of 21758442 is about 279.1746186592.

The spelling of 21758442 in words is "twenty-one million, seven hundred fifty-eight thousand, four hundred forty-two".