21170442 has 16 divisors (see below), whose sum is σ = 44182080. Its totient is φ = 6749952.

The previous prime is 21170441. The next prime is 21170453. The reversal of 21170442 is 24407112.

It is a happy number.

It is a super-2 number, since 2×21170442² = 896375228950728, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21170441) 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, 76567 + ... + 76842.

It is an arithmetic number, because the mean of its divisors is an integer number (2761380).

Almost surely, 2^21170442 is an apocalyptic number.

21170442 is an abundant number, since it is smaller than the sum of its proper divisors (23011638).

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

21170442 is a wasteful number, since it uses less digits than its factorization.

21170442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153437.

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

The square root of 21170442 is about 4601.1348600101. The cubic root of 21170442 is about 276.6368145724.

Adding to 21170442 its reverse (24407112), we get a palindrome (45577554).

It can be divided in two parts, 21170 and 442, that added together give a palindrome (21612).

The spelling of 21170442 in words is "twenty-one million, one hundred seventy thousand, four hundred forty-two".