21557154 has 8 divisors (see below), whose sum is σ = 43114320. Its totient is φ = 7185716.

The previous prime is 21557143. The next prime is 21557177. The reversal of 21557154 is 45175512.

It is a sphenic number, since it is the product of 3 distinct primes.

21557154 is an admirable number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1796424 + ... + 1796435.

It is an arithmetic number, because the mean of its divisors is an integer number (5389290).

Almost surely, 2^21557154 is an apocalyptic number.

21557154 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21557154 is a wasteful number, since it uses less digits than its factorization.

21557154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3592864.

The product of its digits is 7000, while the sum is 30.

The square root of 21557154 is about 4642.9682316380. The cubic root of 21557154 is about 278.3110659833.

The spelling of 21557154 in words is "twenty-one million, five hundred fifty-seven thousand, one hundred fifty-four".