21807012 has 48 divisors (see below), whose sum is σ = 53441024. Its totient is φ = 6919200.

The previous prime is 21807007. The next prime is 21807029. The reversal of 21807012 is 21070812.

It is a self number, because there is not a number n which added to its sum of digits gives 21807012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 357462 + ... + 357522.

Almost surely, 2^21807012 is an apocalyptic number.

It is an amenable number.

21807012 is an abundant number, since it is smaller than the sum of its proper divisors (31634012).

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

21807012 is an equidigital number, since it uses as much as digits as its factorization.

21807012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 21807012 is about 4669.7978542973. The cubic root of 21807012 is about 279.3821922586.

Adding to 21807012 its reverse (21070812), we get a palindrome (42877824).

The spelling of 21807012 in words is "twenty-one million, eight hundred seven thousand, twelve".