20387997 has 16 divisors (see below), whose sum is σ = 34519680. Its totient is φ = 11650176.

The previous prime is 20387993. The next prime is 20388013. The reversal of 20387997 is 79978302.

It is not a de Polignac number, because 20387997 - 2² = 20387993 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20387993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53748 + ... + 54125.

It is an arithmetic number, because the mean of its divisors is an integer number (2157480).

Almost surely, 2^20387997 is an apocalyptic number.

20387997 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

20387997 is a deficient number, since it is larger than the sum of its proper divisors (14131683).

20387997 is a wasteful number, since it uses less digits than its factorization.

20387997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107889 (or 107883 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 20387997 is about 4515.3069663092. The cubic root of 20387997 is about 273.1858413404.

The spelling of 20387997 in words is "twenty million, three hundred eighty-seven thousand, nine hundred ninety-seven".