21554402 has 8 divisors (see below), whose sum is σ = 34233516. Its totient is φ = 10143232.

The previous prime is 21554383. The next prime is 21554443. The reversal of 21554402 is 20445512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21446161 + 108241 = 4631^2 + 329^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 316943 + ... + 317010.

Almost surely, 2^21554402 is an apocalyptic number.

21554402 is a deficient number, since it is larger than the sum of its proper divisors (12679114).

21554402 is a wasteful number, since it uses less digits than its factorization.

21554402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633972.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 21554402 is about 4642.6718600392. The cubic root of 21554402 is about 278.2992223567.

Adding to 21554402 its reverse (20445512), we get a palindrome (41999914).

The spelling of 21554402 in words is "twenty-one million, five hundred fifty-four thousand, four hundred two".