21321706 has 32 divisors (see below), whose sum is σ = 39128832. Its totient is φ = 8505600.

The previous prime is 21321683. The next prime is 21321709. The reversal of 21321706 is 60712312.

It is not an unprimeable number, because it can be changed into a prime (21321709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23595 + ... + 24481.

It is an arithmetic number, because the mean of its divisors is an integer number (1222776).

Almost surely, 2^21321706 is an apocalyptic number.

21321706 is a deficient number, since it is larger than the sum of its proper divisors (17807126).

21321706 is a wasteful number, since it uses less digits than its factorization.

21321706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1014.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 21321706 is about 4617.5432862075. The cubic root of 21321706 is about 277.2941134417.

The spelling of 21321706 in words is "twenty-one million, three hundred twenty-one thousand, seven hundred six".