21017442 has 16 divisors (see below), whose sum is σ = 43391232. Its totient is φ = 6779760.

The previous prime is 21017419. The next prime is 21017453. The reversal of 21017442 is 24471012.

It is a happy 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, 56313 + ... + 56684.

It is an arithmetic number, because the mean of its divisors is an integer number (2711952).

Almost surely, 2^21017442 is an apocalyptic number.

21017442 is an abundant number, since it is smaller than the sum of its proper divisors (22373790).

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

21017442 is a wasteful number, since it uses less digits than its factorization.

21017442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113033.

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 21017442 is about 4584.4783781800. The cubic root of 21017442 is about 275.9687792872.

Adding to 21017442 its reverse (24471012), we get a palindrome (45488454).

The spelling of 21017442 in words is "twenty-one million, seventeen thousand, four hundred forty-two".