20709651 has 4 divisors (see below), whose sum is σ = 27612872. Its totient is φ = 13806432.

The previous prime is 20709641. The next prime is 20709653. The reversal of 20709651 is 15690702.

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

It is not a de Polignac number, because 20709651 - 2⁷ = 20709523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20709653) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3451606 + ... + 3451611.

It is an arithmetic number, because the mean of its divisors is an integer number (6903218).

Almost surely, 2^20709651 is an apocalyptic number.

20709651 is a deficient number, since it is larger than the sum of its proper divisors (6903221).

20709651 is an equidigital number, since it uses as much as digits as its factorization.

20709651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6903220.

The product of its (nonzero) digits is 3780, while the sum is 30.

The square root of 20709651 is about 4550.7857563282. The cubic root of 20709651 is about 274.6150028573.

The spelling of 20709651 in words is "twenty million, seven hundred nine thousand, six hundred fifty-one".