18961857 has 20 divisors (see below), whose sum is σ = 28557936. Its totient is φ = 12537720.

The previous prime is 18961847. The next prime is 18961879. The reversal of 18961857 is 75816981.

It is not a de Polignac number, because 18961857 - 2⁶ = 18961793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18961807) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9718 + ... + 11504.

Almost surely, 2^18961857 is an apocalyptic number.

It is an amenable number.

18961857 is a deficient number, since it is larger than the sum of its proper divisors (9596079).

18961857 is a wasteful number, since it uses less digits than its factorization.

18961857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1930 (or 1921 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 18961857 is about 4354.5214432817. The cubic root of 18961857 is about 266.6614823645.

The spelling of 18961857 in words is "eighteen million, nine hundred sixty-one thousand, eight hundred fifty-seven".