21630785 has 8 divisors (see below), whose sum is σ = 28316736. Its totient is φ = 15731440.

The previous prime is 21630779. The next prime is 21630841. The reversal of 21630785 is 58703612.

It is a happy number.

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

It is not a de Polignac number, because 21630785 - 2⁴ = 21630769 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196589 + ... + 196698.

It is an arithmetic number, because the mean of its divisors is an integer number (3539592).

Almost surely, 2^21630785 is an apocalyptic number.

It is an amenable number.

21630785 is a deficient number, since it is larger than the sum of its proper divisors (6685951).

21630785 is a wasteful number, since it uses less digits than its factorization.

21630785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393303.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21630785 is about 4650.8907748946. The cubic root of 21630785 is about 278.6275739812.

The spelling of 21630785 in words is "twenty-one million, six hundred thirty thousand, seven hundred eighty-five".