20328557 has 2 divisors, whose sum is σ = 20328558. Its totient is φ = 20328556.

The previous prime is 20328547. The next prime is 20328569. The reversal of 20328557 is 75582302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18957316 + 1371241 = 4354^2 + 1171^2 .

It is a cyclic number.

It is not a de Polignac number, because 20328557 - 2⁴ = 20328541 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20328547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10164278 + 10164279.

It is an arithmetic number, because the mean of its divisors is an integer number (10164279).

Almost surely, 2^20328557 is an apocalyptic number.

It is an amenable number.

20328557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20328557 is an equidigital number, since it uses as much as digits as its factorization.

20328557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16800, while the sum is 32.

The square root of 20328557 is about 4508.7201066378. The cubic root of 20328557 is about 272.9200971954.

The spelling of 20328557 in words is "twenty million, three hundred twenty-eight thousand, five hundred fifty-seven".