20219557 has 2 divisors, whose sum is σ = 20219558. Its totient is φ = 20219556.

The previous prime is 20219539. The next prime is 20219569. The reversal of 20219557 is 75591202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17757796 + 2461761 = 4214^2 + 1569^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20219557 is a prime.

It is equal to p_1283638 and since 20219557 and 1283638 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20219527) 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 as a sum of consecutive naturals, namely, 10109778 + 10109779.

It is an arithmetic number, because the mean of its divisors is an integer number (10109779).

Almost surely, 2^20219557 is an apocalyptic number.

It is an amenable number.

20219557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20219557 is an equidigital number, since it uses as much as digits as its factorization.

20219557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6300, while the sum is 31.

The square root of 20219557 is about 4496.6161721899. The cubic root of 20219557 is about 272.4314312789.

The spelling of 20219557 in words is "twenty million, two hundred nineteen thousand, five hundred fifty-seven".