21425870 has 8 divisors (see below), whose sum is σ = 38566584. Its totient is φ = 8570344.

The previous prime is 21425851. The next prime is 21425881. The reversal of 21425870 is 7852412.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1071284 + ... + 1071303.

It is an arithmetic number, because the mean of its divisors is an integer number (4820823).

Almost surely, 2^21425870 is an apocalyptic number.

21425870 is a deficient number, since it is larger than the sum of its proper divisors (17140714).

21425870 is a wasteful number, since it uses less digits than its factorization.

21425870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142594.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21425870 is about 4628.8087020312. The cubic root of 21425870 is about 277.7449397033.

The spelling of 21425870 in words is "twenty-one million, four hundred twenty-five thousand, eight hundred seventy".