21542044 has 6 divisors (see below), whose sum is σ = 37698584. Its totient is φ = 10771020.

The previous prime is 21541979. The next prime is 21542063. The reversal of 21542044 is 44024512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2692752 + ... + 2692759.

Almost surely, 2^21542044 is an apocalyptic number.

It is an amenable number.

21542044 is a deficient number, since it is larger than the sum of its proper divisors (16156540).

21542044 is a wasteful number, since it uses less digits than its factorization.

21542044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5385515 (or 5385513 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21542044 is about 4641.3407545665. The cubic root of 21542044 is about 278.2460255003.

Adding to 21542044 its reverse (44024512), we get a palindrome (65566556).

The spelling of 21542044 in words is "twenty-one million, five hundred forty-two thousand, forty-four".