20755557 has 24 divisors (see below), whose sum is σ = 31064696. Its totient is φ = 13343616.

The previous prime is 20755547. The next prime is 20755571. The reversal of 20755557 is 75555702.

It can be written as a sum of positive squares in 4 ways, for example, as 6625476 + 14130081 = 2574^2 + 3759^2 .

It is not a de Polignac number, because 20755557 - 2¹⁹ = 20231269 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 (20755507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 52083 + ... + 52479.

Almost surely, 2^20755557 is an apocalyptic number.

It is an amenable number.

20755557 is a deficient number, since it is larger than the sum of its proper divisors (10309139).

20755557 is a wasteful number, since it uses less digits than its factorization.

20755557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597 (or 594 counting only the distinct ones).

The product of its (nonzero) digits is 61250, while the sum is 36.

The square root of 20755557 is about 4555.8267087325. The cubic root of 20755557 is about 274.8177613533.

It can be divided in two parts, 20755 and 557, that added together give a palindrome (21312).

The spelling of 20755557 in words is "twenty million, seven hundred fifty-five thousand, five hundred fifty-seven".