20553857 has 4 divisors (see below), whose sum is σ = 20591316. Its totient is φ = 20516400.

The previous prime is 20553853. The next prime is 20553887. The reversal of 20553857 is 75835502.

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 982081 + 19571776 = 991^2 + 4424^2 .

It is a cyclic number.

It is not a de Polignac number, because 20553857 - 2² = 20553853 is a prime.

It is a super-2 number, since 2×20553857² = 844922075152898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20553853) 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, 17894 + ... + 19007.

It is an arithmetic number, because the mean of its divisors is an integer number (5147829).

Almost surely, 2^20553857 is an apocalyptic number.

It is an amenable number.

20553857 is a deficient number, since it is larger than the sum of its proper divisors (37459).

20553857 is an equidigital number, since it uses as much as digits as its factorization.

20553857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37458.

The product of its (nonzero) digits is 42000, while the sum is 35.

The square root of 20553857 is about 4533.6361786098. The cubic root of 20553857 is about 273.9246467269.

The spelling of 20553857 in words is "twenty million, five hundred fifty-three thousand, eight hundred fifty-seven".