20761591 has 2 divisors, whose sum is σ = 20761592. Its totient is φ = 20761590.

The previous prime is 20761577. The next prime is 20761613. The reversal of 20761591 is 19516702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20761591 - 2⁷ = 20761463 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20761501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10380795 + 10380796.

It is an arithmetic number, because the mean of its divisors is an integer number (10380796).

Almost surely, 2^20761591 is an apocalyptic number.

20761591 is a deficient number, since it is larger than the sum of its proper divisors (1).

20761591 is an equidigital number, since it uses as much as digits as its factorization.

20761591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 20761591 is about 4556.4888894850. The cubic root of 20761591 is about 274.8443902011.

The spelling of 20761591 in words is "twenty million, seven hundred sixty-one thousand, five hundred ninety-one".