20397811 has 16 divisors (see below), whose sum is σ = 24793600. Its totient is φ = 16391808.

The previous prime is 20397809. The next prime is 20397823. The reversal of 20397811 is 11879302.

It is a cyclic number.

It is not a de Polignac number, because 20397811 - 2¹ = 20397809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20397211) 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 15 ways as a sum of consecutive naturals, for example, 12955 + ... + 14443.

It is an arithmetic number, because the mean of its divisors is an integer number (1549600).

Almost surely, 2^20397811 is an apocalyptic number.

20397811 is a deficient number, since it is larger than the sum of its proper divisors (4395789).

20397811 is a wasteful number, since it uses less digits than its factorization.

20397811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1618.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 20397811 is about 4516.3935833804. The cubic root of 20397811 is about 273.2296680387.

The spelling of 20397811 in words is "twenty million, three hundred ninety-seven thousand, eight hundred eleven".