20397511 has 2 divisors, whose sum is σ = 20397512. Its totient is φ = 20397510.

The previous prime is 20397479. The next prime is 20397529. The reversal of 20397511 is 11579302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20397511 - 2⁵ = 20397479 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20397511.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20397551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10198755 + 10198756.

It is an arithmetic number, because the mean of its divisors is an integer number (10198756).

Almost surely, 2^20397511 is an apocalyptic number.

20397511 is a deficient number, since it is larger than the sum of its proper divisors (1).

20397511 is an equidigital number, since it uses as much as digits as its factorization.

20397511 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 20397511 is about 4516.3603709182. The cubic root of 20397511 is about 273.2283285272.

The spelling of 20397511 in words is "twenty million, three hundred ninety-seven thousand, five hundred eleven".