21423550 has 12 divisors (see below), whose sum is σ = 39847896. Its totient is φ = 8569400.

The previous prime is 21423539. The next prime is 21423559. The reversal of 21423550 is 5532412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423559) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214186 + ... + 214285.

It is an arithmetic number, because the mean of its divisors is an integer number (3320658).

Almost surely, 2^21423550 is an apocalyptic number.

21423550 is a deficient number, since it is larger than the sum of its proper divisors (18424346).

21423550 is a wasteful number, since it uses less digits than its factorization.

21423550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428483 (or 428478 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21423550 is about 4628.5580908097. The cubic root of 21423550 is about 277.7349145714.

Adding to 21423550 its reverse (5532412), we get a palindrome (26955962).

The spelling of 21423550 in words is "twenty-one million, four hundred twenty-three thousand, five hundred fifty".