21012258 has 8 divisors (see below), whose sum is σ = 42024528. Its totient is φ = 7004084.

The previous prime is 21012241. The next prime is 21012259. The reversal of 21012258 is 85221012.

It is a happy number.

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

21012258 is an admirable number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21012259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751016 + ... + 1751027.

It is an arithmetic number, because the mean of its divisors is an integer number (5253066).

Almost surely, 2^21012258 is an apocalyptic number.

21012258 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21012258 is a wasteful number, since it uses less digits than its factorization.

21012258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502048.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 21012258 is about 4583.9129572888. The cubic root of 21012258 is about 275.9460879786.

The spelling of 21012258 in words is "twenty-one million, twelve thousand, two hundred fifty-eight".