21153642 has 32 divisors (see below), whose sum is σ = 43447104. Its totient is φ = 6864000.

The previous prime is 21153637. The next prime is 21153653. The reversal of 21153642 is 24635112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40342 + ... + 40862.

It is an arithmetic number, because the mean of its divisors is an integer number (1357722).

Almost surely, 2^21153642 is an apocalyptic number.

21153642 is an abundant number, since it is smaller than the sum of its proper divisors (22293462).

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

21153642 is a wasteful number, since it uses less digits than its factorization.

21153642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694.

The product of its digits is 1440, while the sum is 24.

The square root of 21153642 is about 4599.3088611225. The cubic root of 21153642 is about 276.5636193067.

Adding to 21153642 its reverse (24635112), we get a palindrome (45788754).

The spelling of 21153642 in words is "twenty-one million, one hundred fifty-three thousand, six hundred forty-two".