21772554 has 8 divisors (see below), whose sum is σ = 43545120. Its totient is φ = 7257516.

The previous prime is 21772549. The next prime is 21772561. The reversal of 21772554 is 45527712.

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

21772554 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1814374 + ... + 1814385.

It is an arithmetic number, because the mean of its divisors is an integer number (5443140).

Almost surely, 2^21772554 is an apocalyptic number.

21772554 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.

21772554 is a wasteful number, since it uses less digits than its factorization.

21772554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3628764.

The product of its digits is 19600, while the sum is 33.

The square root of 21772554 is about 4666.1069426236. The cubic root of 21772554 is about 279.2349609207.

It can be divided in two parts, 217 and 72554, that added together give a triangular number (72771 = T₃₈₁).

The spelling of 21772554 in words is "twenty-one million, seven hundred seventy-two thousand, five hundred fifty-four".