20551577 has 2 divisors, whose sum is σ = 20551578. Its totient is φ = 20551576.

The previous prime is 20551561. The next prime is 20551579. The reversal of 20551577 is 77515502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20214016 + 337561 = 4496^2 + 581^2 .

It is a cyclic number.

It is not a de Polignac number, because 20551577 - 2⁴ = 20551561 is a prime.

Together with 20551579, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20551579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10275788 + 10275789.

It is an arithmetic number, because the mean of its divisors is an integer number (10275789).

Almost surely, 2^20551577 is an apocalyptic number.

It is an amenable number.

20551577 is a deficient number, since it is larger than the sum of its proper divisors (1).

20551577 is an equidigital number, since it uses as much as digits as its factorization.

20551577 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12250, while the sum is 32.

The square root of 20551577 is about 4533.3847178460. The cubic root of 20551577 is about 273.9145177069.

The spelling of 20551577 in words is "twenty million, five hundred fifty-one thousand, five hundred seventy-seven".