21245670 has 24 divisors (see below), whose sum is σ = 55238976. Its totient is φ = 5665488.

The previous prime is 21245669. The next prime is 21245683. The reversal of 21245670 is 7654212.

It is a Curzon number.

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, 117942 + ... + 118121.

It is an arithmetic number, because the mean of its divisors is an integer number (2301624).

Almost surely, 2^21245670 is an apocalyptic number.

21245670 is an abundant number, since it is smaller than the sum of its proper divisors (33993306).

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

21245670 is a wasteful number, since it uses less digits than its factorization.

21245670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236076 (or 236073 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21245670 is about 4609.3025502781. The cubic root of 21245670 is about 276.9640984458.

Adding to 21245670 its reverse (7654212), we get a palindrome (28899882).

The spelling of 21245670 in words is "twenty-one million, two hundred forty-five thousand, six hundred seventy".