21554151 has 32 divisors (see below), whose sum is σ = 32417280. Its totient is φ = 12672000.

The previous prime is 21554149. The next prime is 21554161. The reversal of 21554151 is 15145512.

It is not a de Polignac number, because 21554151 - 2¹ = 21554149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554111) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 53551 + ... + 53951.

It is an arithmetic number, because the mean of its divisors is an integer number (1013040).

Almost surely, 2^21554151 is an apocalyptic number.

21554151 is a deficient number, since it is larger than the sum of its proper divisors (10863129).

21554151 is a wasteful number, since it uses less digits than its factorization.

21554151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487.

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

The square root of 21554151 is about 4642.6448281125. The cubic root of 21554151 is about 278.2981420920.

Adding to 21554151 its reverse (15145512), we get a palindrome (36699663).

The spelling of 21554151 in words is "twenty-one million, five hundred fifty-four thousand, one hundred fifty-one".