21726730 has 8 divisors (see below), whose sum is σ = 39108132. Its totient is φ = 8690688.

The previous prime is 21726721. The next prime is 21726791. The reversal of 21726730 is 3762712.

It can be written as a sum of positive squares in 2 ways, for example, as 21706281 + 20449 = 4659^2 + 143^2 .

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

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, 1086327 + ... + 1086346.

Almost surely, 2^21726730 is an apocalyptic number.

21726730 is a deficient number, since it is larger than the sum of its proper divisors (17381402).

21726730 is a wasteful number, since it uses less digits than its factorization.

21726730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2172680.

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 21726730 is about 4661.1940530298. The cubic root of 21726730 is about 279.0389243535.

The spelling of 21726730 in words is "twenty-one million, seven hundred twenty-six thousand, seven hundred thirty".