20147557 has 4 divisors (see below), whose sum is σ = 20168460. Its totient is φ = 20126656.

The previous prime is 20147549. The next prime is 20147587. The reversal of 20147557 is 75574102.

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 8099716 + 12047841 = 2846^2 + 3471^2 .

It is a cyclic number.

It is not a de Polignac number, because 20147557 - 2³ = 20147549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20147587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8932 + ... + 10957.

It is an arithmetic number, because the mean of its divisors is an integer number (5042115).

Almost surely, 2^20147557 is an apocalyptic number.

It is an amenable number.

20147557 is a deficient number, since it is larger than the sum of its proper divisors (20903).

20147557 is a wasteful number, since it uses less digits than its factorization.

20147557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20902.

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

The square root of 20147557 is about 4488.6030120740. The cubic root of 20147557 is about 272.1076788560.

The spelling of 20147557 in words is "twenty million, one hundred forty-seven thousand, five hundred fifty-seven".