21657070 has 8 divisors (see below), whose sum is σ = 38982744. Its totient is φ = 8662824.

The previous prime is 21657067. The next prime is 21657137. The reversal of 21657070 is 7075612.

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, 1082844 + ... + 1082863.

It is an arithmetic number, because the mean of its divisors is an integer number (4872843).

Almost surely, 2^21657070 is an apocalyptic number.

21657070 is a deficient number, since it is larger than the sum of its proper divisors (17325674).

21657070 is a wasteful number, since it uses less digits than its factorization.

21657070 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2165714.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 21657070 is about 4653.7157197233. The cubic root of 21657070 is about 278.7403879061.

The spelling of 21657070 in words is "twenty-one million, six hundred fifty-seven thousand, seventy".