20397757 has 4 divisors (see below), whose sum is σ = 21284640. Its totient is φ = 19510876.

The previous prime is 20397749. The next prime is 20397763. The reversal of 20397757 is 75779302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20397757 - 2³ = 20397749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397737) 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 in 3 ways as a sum of consecutive naturals, for example, 443407 + ... + 443452.

It is an arithmetic number, because the mean of its divisors is an integer number (5321160).

Almost surely, 2^20397757 is an apocalyptic number.

It is an amenable number.

20397757 is a deficient number, since it is larger than the sum of its proper divisors (886883).

20397757 is an equidigital number, since it uses as much as digits as its factorization.

20397757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 886882.

The product of its (nonzero) digits is 92610, while the sum is 40.

The square root of 20397757 is about 4516.3876051553. The cubic root of 20397757 is about 273.2294269276.

The spelling of 20397757 in words is "twenty million, three hundred ninety-seven thousand, seven hundred fifty-seven".