1866081640 has 32 divisors (see below), whose sum is σ = 4257826560. Its totient is φ = 735918400.

The previous prime is 1866081631. The next prime is 1866081649. The reversal of 1866081640 is 461806681.

It is an interprime number because it is at equal distance from previous prime (1866081631) and next prime (1866081649).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 1866081593 and 1866081602.

It is not an unprimeable number, because it can be changed into a prime (1866081649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 325696 + ... + 331375.

It is an arithmetic number, because the mean of its divisors is an integer number (133057080).

Almost surely, 2^1866081640 is an apocalyptic number.

1866081640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1866081640 is an abundant number, since it is smaller than the sum of its proper divisors (2391744920).

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

1866081640 is a wasteful number, since it uses less digits than its factorization.

1866081640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 657153 (or 657149 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 1866081640 is about 43198.1670907459. The cubic root of 1866081640 is about 1231.1478565750.

The spelling of 1866081640 in words is "one billion, eight hundred sixty-six million, eighty-one thousand, six hundred forty".