1671405840 has 200 divisors, whose sum is σ = 6251896728. Its totient is φ = 411402240.

The previous prime is 1671405839. The next prime is 1671405859. The reversal of 1671405840 is 485041761.

It is a happy number.

1671405840 is a `hidden beast` number, since 1 + 6 + 71 + 4 + 0 + 584 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 80353296 + 1591052544 = 8964^2 + 39888^2 .

It is a super-2 number, since 2×1671405840² = 5587194963972211200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1671405795 and 1671405804.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 74320 + ... + 94160.

Almost surely, 2^1671405840 is an apocalyptic number.

1671405840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1671405840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3125948364).

1671405840 is an abundant number, since it is smaller than the sum of its proper divisors (4580490888).

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

1671405840 is a wasteful number, since it uses less digits than its factorization.

1671405840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19879 (or 19864 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 1671405840 is about 40882.8306260709. The cubic root of 1671405840 is about 1186.7538202763.

The spelling of 1671405840 in words is "one billion, six hundred seventy-one million, four hundred five thousand, eight hundred forty".