20740691 has 2 divisors, whose sum is σ = 20740692. Its totient is φ = 20740690.

The previous prime is 20740679. The next prime is 20740693. The reversal of 20740691 is 19604702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20740691 - 2¹⁸ = 20478547 is a prime.

Together with 20740693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20740693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10370345 + 10370346.

It is an arithmetic number, because the mean of its divisors is an integer number (10370346).

Almost surely, 2^20740691 is an apocalyptic number.

20740691 is a deficient number, since it is larger than the sum of its proper divisors (1).

20740691 is an equidigital number, since it uses as much as digits as its factorization.

20740691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 20740691 is about 4554.1948794491. The cubic root of 20740691 is about 274.7521336821.

The spelling of 20740691 in words is "twenty million, seven hundred forty thousand, six hundred ninety-one".