20557970 has 16 divisors (see below), whose sum is σ = 37079640. Its totient is φ = 8206464.

The previous prime is 20557967. The next prime is 20557973. The reversal of 20557970 is 7975502.

It is an interprime number because it is at equal distance from previous prime (20557967) and next prime (20557973).

It can be written as a sum of positive squares in 4 ways, for example, as 5480281 + 15077689 = 2341^2 + 3883^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20557970.

It is not an unprimeable number, because it can be changed into a prime (20557973) 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 7 ways as a sum of consecutive naturals, for example, 3884 + ... + 7496.

Almost surely, 2^20557970 is an apocalyptic number.

20557970 is a deficient number, since it is larger than the sum of its proper divisors (16521670).

20557970 is a wasteful number, since it uses less digits than its factorization.

20557970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4189.

The product of its (nonzero) digits is 22050, while the sum is 35.

The square root of 20557970 is about 4534.0897653223. The cubic root of 20557970 is about 273.9429170517.

The spelling of 20557970 in words is "twenty million, five hundred fifty-seven thousand, nine hundred seventy".