21551154 has 16 divisors (see below), whose sum is σ = 43261248. Its totient is φ = 7157232.

The previous prime is 21551143. The next prime is 21551171. The reversal of 21551154 is 45115512.

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, 4822 + ... + 8145.

It is an arithmetic number, because the mean of its divisors is an integer number (2703828).

Almost surely, 2^21551154 is an apocalyptic number.

21551154 is an abundant number, since it is smaller than the sum of its proper divisors (21710094).

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

21551154 is a wasteful number, since it uses less digits than its factorization.

21551154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13249.

The product of its digits is 1000, while the sum is 24.

The square root of 21551154 is about 4642.3220482857. The cubic root of 21551154 is about 278.2852428258.

Adding to 21551154 its reverse (45115512), we get a palindrome (66666666).

The spelling of 21551154 in words is "twenty-one million, five hundred fifty-one thousand, one hundred fifty-four".