21723470 has 8 divisors (see below), whose sum is σ = 39102264. Its totient is φ = 8689384.

The previous prime is 21723469. The next prime is 21723539. The reversal of 21723470 is 7432712.

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

It is a plaindrome in base 9.

It is a zygodrome in base 9.

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, 1086164 + ... + 1086183.

It is an arithmetic number, because the mean of its divisors is an integer number (4887783).

Almost surely, 2^21723470 is an apocalyptic number.

21723470 is a deficient number, since it is larger than the sum of its proper divisors (17378794).

21723470 is a wasteful number, since it uses less digits than its factorization.

21723470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2172354.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 21723470 is about 4660.8443441076. The cubic root of 21723470 is about 279.0249674688.

The spelling of 21723470 in words is "twenty-one million, seven hundred twenty-three thousand, four hundred seventy".