19887057 has 18 divisors (see below), whose sum is σ = 29165058. Its totient is φ = 13057632.

The previous prime is 19887041. The next prime is 19887061. The reversal of 19887057 is 75078891.

It can be written as a sum of positive squares in only one way, i.e., 17564481 + 2322576 = 4191^2 + 1524^2 .

It is not a de Polignac number, because 19887057 - 2⁴ = 19887041 is a prime.

It is a super-2 number, since 2×19887057² = 790990072242498, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19887017) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 145093 + ... + 145229.

It is an arithmetic number, because the mean of its divisors is an integer number (1620281).

Almost surely, 2^19887057 is an apocalyptic number.

It is an amenable number.

19887057 is a deficient number, since it is larger than the sum of its proper divisors (9278001).

19887057 is a wasteful number, since it uses less digits than its factorization.

19887057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The square root of 19887057 is about 4459.4906659842. The cubic root of 19887057 is about 270.9298393647.

It can be divided in two parts, 1988 and 7057, that added together give a triangular number (9045 = T₁₃₄).

The spelling of 19887057 in words is "nineteen million, eight hundred eighty-seven thousand, fifty-seven".