21297706 has 4 divisors (see below), whose sum is σ = 31946562. Its totient is φ = 10648852.

The previous prime is 21297691. The next prime is 21297733. The reversal of 21297706 is 60779212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11964681 + 9333025 = 3459^2 + 3055^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5324425 + ... + 5324428.

Almost surely, 2^21297706 is an apocalyptic number.

21297706 is a deficient number, since it is larger than the sum of its proper divisors (10648856).

21297706 is a wasteful number, since it uses less digits than its factorization.

21297706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10648855.

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 21297706 is about 4614.9437699716. The cubic root of 21297706 is about 277.1900323815.

The spelling of 21297706 in words is "twenty-one million, two hundred ninety-seven thousand, seven hundred six".