1866491556 has 12 divisors (see below), whose sum is σ = 4355146992. Its totient is φ = 622163848.

The previous prime is 1866491527. The next prime is 1866491563. The reversal of 1866491556 is 6551946681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×1866491556² = 6967581457238602272, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1866491499 and 1866491508.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77770470 + ... + 77770493.

It is an arithmetic number, because the mean of its divisors is an integer number (362928916).

Almost surely, 2^1866491556 is an apocalyptic number.

It is an amenable number.

1866491556 is an abundant number, since it is smaller than the sum of its proper divisors (2488655436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1866491556 is a wasteful number, since it uses less digits than its factorization.

1866491556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155540970 (or 155540968 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 51.

The square root of 1866491556 is about 43202.9114296710. The cubic root of 1866491556 is about 1231.2379973715.

The spelling of 1866491556 in words is "one billion, eight hundred sixty-six million, four hundred ninety-one thousand, five hundred fifty-six".