21673970 has 16 divisors (see below), whose sum is σ = 39121920. Its totient is φ = 8645424.

The previous prime is 21673969. The next prime is 21673973. The reversal of 21673970 is 7937612.

It is a self number, because there is not a number n which added to its sum of digits gives 21673970.

It is not an unprimeable number, because it can be changed into a prime (21673973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1001 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (2445120).

Almost surely, 2^21673970 is an apocalyptic number.

21673970 is a deficient number, since it is larger than the sum of its proper divisors (17447950).

21673970 is a wasteful number, since it uses less digits than its factorization.

21673970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6049.

The product of its (nonzero) digits is 15876, while the sum is 35.

The square root of 21673970 is about 4655.5311190024. The cubic root of 21673970 is about 278.8128736696.

The spelling of 21673970 in words is "twenty-one million, six hundred seventy-three thousand, nine hundred seventy".