20503557 has 32 divisors (see below), whose sum is σ = 32060160. Its totient is φ = 12925440.

The previous prime is 20503537. The next prime is 20503577. The reversal of 20503557 is 75530502.

It is an interprime number because it is at equal distance from previous prime (20503537) and next prime (20503577).

It is not a de Polignac number, because 20503557 - 2⁷ = 20503429 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 20503557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20503507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 84957 + ... + 85197.

It is an arithmetic number, because the mean of its divisors is an integer number (1001880).

Almost surely, 2^20503557 is an apocalyptic number.

20503557 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

20503557 is a deficient number, since it is larger than the sum of its proper divisors (11556603).

20503557 is a wasteful number, since it uses less digits than its factorization.

20503557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410 (or 404 counting only the distinct ones).

The product of its (nonzero) digits is 5250, while the sum is 27.

The square root of 20503557 is about 4528.0853569693. The cubic root of 20503557 is about 273.7010120635.

The spelling of 20503557 in words is "twenty million, five hundred three thousand, five hundred fifty-seven".