21280670 has 8 divisors (see below), whose sum is σ = 38305224. Its totient is φ = 8512264.

The previous prime is 21280639. The next prime is 21280687. The reversal of 21280670 is 7608212.

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

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 3 ways as a sum of consecutive naturals, for example, 1064024 + ... + 1064043.

It is an arithmetic number, because the mean of its divisors is an integer number (4788153).

Almost surely, 2^21280670 is an apocalyptic number.

21280670 is a deficient number, since it is larger than the sum of its proper divisors (17024554).

21280670 is a wasteful number, since it uses less digits than its factorization.

21280670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2128074.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21280670 is about 4613.0976577567. The cubic root of 21280670 is about 277.1161047162.

Adding to 21280670 its reverse (7608212), we get a palindrome (28888882).

The spelling of 21280670 in words is "twenty-one million, two hundred eighty thousand, six hundred seventy".