20591387 has 4 divisors (see below), whose sum is σ = 20839560. Its totient is φ = 20343216.

The previous prime is 20591377. The next prime is 20591407. The reversal of 20591387 is 78319502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20591387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20591317) 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 3 ways as a sum of consecutive naturals, for example, 123962 + ... + 124127.

It is an arithmetic number, because the mean of its divisors is an integer number (5209890).

Almost surely, 2^20591387 is an apocalyptic number.

20591387 is a deficient number, since it is larger than the sum of its proper divisors (248173).

20591387 is an equidigital number, since it uses as much as digits as its factorization.

20591387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248172.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20591387 is about 4537.7733526477. The cubic root of 20591387 is about 274.0912681908.

The spelling of 20591387 in words is "twenty million, five hundred ninety-one thousand, three hundred eighty-seven".