21255030 has 24 divisors (see below), whose sum is σ = 55263312. Its totient is φ = 5667984.

The previous prime is 21255019. The next prime is 21255061. The reversal of 21255030 is 3055212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21254994 and 21255012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 117994 + ... + 118173.

It is an arithmetic number, because the mean of its divisors is an integer number (2302638).

Almost surely, 2^21255030 is an apocalyptic number.

21255030 is an abundant number, since it is smaller than the sum of its proper divisors (34008282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21255030 is a wasteful number, since it uses less digits than its factorization.

21255030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236180 (or 236177 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21255030 is about 4610.3177764662. The cubic root of 21255030 is about 277.0047656085.

The spelling of 21255030 in words is "twenty-one million, two hundred fifty-five thousand, thirty".