20397855 has 8 divisors (see below), whose sum is σ = 32636592. Its totient is φ = 10878848.

The previous prime is 20397847. The next prime is 20397863. The reversal of 20397855 is 55879302.

It is an interprime number because it is at equal distance from previous prime (20397847) and next prime (20397863).

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 20397855 - 2³ = 20397847 is a prime.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 679914 + ... + 679943.

It is an arithmetic number, because the mean of its divisors is an integer number (4079574).

Almost surely, 2^20397855 is an apocalyptic number.

20397855 is a deficient number, since it is larger than the sum of its proper divisors (12238737).

20397855 is a wasteful number, since it uses less digits than its factorization.

20397855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1359865.

The product of its (nonzero) digits is 75600, while the sum is 39.

The square root of 20397855 is about 4516.3984545210. The cubic root of 20397855 is about 273.2298644992.

The spelling of 20397855 in words is "twenty million, three hundred ninety-seven thousand, eight hundred fifty-five".