21798554 has 8 divisors (see below), whose sum is σ = 32879028. Its totient is φ = 10838880.

The previous prime is 21798547. The next prime is 21798559. The reversal of 21798554 is 45589712.

It can be written as a sum of positive squares in 2 ways, for example, as 12355225 + 9443329 = 3515^2 + 3073^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21798559) by changing a digit.

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, 29747 + ... + 30470.

Almost surely, 2^21798554 is an apocalyptic number.

21798554 is a deficient number, since it is larger than the sum of its proper divisors (11080474).

21798554 is a wasteful number, since it uses less digits than its factorization.

21798554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60400.

The product of its digits is 100800, while the sum is 41.

The square root of 21798554 is about 4668.8921598169. The cubic root of 21798554 is about 279.3460674844.

The spelling of 21798554 in words is "twenty-one million, seven hundred ninety-eight thousand, five hundred fifty-four".