20959691 has 8 divisors (see below), whose sum is σ = 22569840. Its totient is φ = 19391488.

The previous prime is 20959667. The next prime is 20959703. The reversal of 20959691 is 19695902.

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

It is a cyclic number.

It is not a de Polignac number, because 20959691 - 2²² = 16765387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20959091) 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, 9446 + ... + 11451.

It is an arithmetic number, because the mean of its divisors is an integer number (2821230).

Almost surely, 2^20959691 is an apocalyptic number.

20959691 is a deficient number, since it is larger than the sum of its proper divisors (1610149).

20959691 is a wasteful number, since it uses less digits than its factorization.

20959691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20973.

The product of its (nonzero) digits is 43740, while the sum is 41.

The square root of 20959691 is about 4578.1755099603. The cubic root of 20959691 is about 275.7157815980.

The spelling of 20959691 in words is "twenty million, nine hundred fifty-nine thousand, six hundred ninety-one".