20381157 has 6 divisors (see below), whose sum is σ = 29439462. Its totient is φ = 13587432.

The previous prime is 20381149. The next prime is 20381159. The reversal of 20381157 is 75118302.

It can be written as a sum of positive squares in only one way, i.e., 19660356 + 720801 = 4434^2 + 849^2 .

It is not a de Polignac number, because 20381157 - 2³ = 20381149 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20381157.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20381159) 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 5 ways as a sum of consecutive naturals, for example, 1132278 + ... + 1132295.

It is an arithmetic number, because the mean of its divisors is an integer number (4906577).

Almost surely, 2^20381157 is an apocalyptic number.

It is an amenable number.

20381157 is a deficient number, since it is larger than the sum of its proper divisors (9058305).

20381157 is a wasteful number, since it uses less digits than its factorization.

20381157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2264579 (or 2264576 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 20381157 is about 4514.5494791839. The cubic root of 20381157 is about 273.1552874127.

Adding to 20381157 its reverse (75118302), we get a palindrome (95499459).

The spelling of 20381157 in words is "twenty million, three hundred eighty-one thousand, one hundred fifty-seven".