21255430 has 16 divisors (see below), whose sum is σ = 43725600. Its totient is φ = 7287552.

The previous prime is 21255419. The next prime is 21255431. The reversal of 21255430 is 3455212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151755 + ... + 151894.

It is an arithmetic number, because the mean of its divisors is an integer number (2732850).

Almost surely, 2^21255430 is an apocalyptic number.

21255430 is an abundant number, since it is smaller than the sum of its proper divisors (22470170).

21255430 is a wasteful number, since it uses less digits than its factorization.

21255430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303663.

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

The square root of 21255430 is about 4610.3611572197. The cubic root of 21255430 is about 277.0065032554.

The spelling of 21255430 in words is "twenty-one million, two hundred fifty-five thousand, four hundred thirty".