20709690 has 16 divisors (see below), whose sum is σ = 49703328. Its totient is φ = 5522576.

The previous prime is 20709671. The next prime is 20709691. The reversal of 20709690 is 9690702.

It is a super-2 number, since 2×20709690² = 857782519792200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20709691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 345132 + ... + 345191.

It is an arithmetic number, because the mean of its divisors is an integer number (3106458).

Almost surely, 2^20709690 is an apocalyptic number.

20709690 is an abundant number, since it is smaller than the sum of its proper divisors (28993638).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20709690 is a wasteful number, since it uses less digits than its factorization.

20709690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 690333.

The product of its (nonzero) digits is 6804, while the sum is 33.

The square root of 20709690 is about 4550.7900413005. The cubic root of 20709690 is about 274.6151752404.

The spelling of 20709690 in words is "twenty million, seven hundred nine thousand, six hundred ninety".