20745157 has 4 divisors (see below), whose sum is σ = 20777580. Its totient is φ = 20712736.

The previous prime is 20745119. The next prime is 20745161. The reversal of 20745157 is 75154702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5134756 + 15610401 = 2266^2 + 3951^2 .

It is a cyclic number.

It is not a de Polignac number, because 20745157 - 2¹⁹ = 20220869 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20755157) 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, 15232 + ... + 16537.

It is an arithmetic number, because the mean of its divisors is an integer number (5194395).

Almost surely, 2^20745157 is an apocalyptic number.

It is an amenable number.

20745157 is a deficient number, since it is larger than the sum of its proper divisors (32423).

20745157 is an equidigital number, since it uses as much as digits as its factorization.

20745157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32422.

The product of its (nonzero) digits is 9800, while the sum is 31.

The square root of 20745157 is about 4554.6851702395. The cubic root of 20745157 is about 274.7718526485.

Adding to 20745157 its reverse (75154702), we get a palindrome (95899859).

It can be divided in two parts, 20745 and 157, that added together give a palindrome (20902).

The spelling of 20745157 in words is "twenty million, seven hundred forty-five thousand, one hundred fifty-seven".