1641261840 has 160 divisors (see below), whose sum is σ = 5232522240. Its totient is φ = 425338368.

The previous prime is 1641261827. The next prime is 1641261859. The reversal of 1641261840 is 481621461.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3704659 + ... + 3705101.

It is an arithmetic number, because the mean of its divisors is an integer number (32703264).

Almost surely, 2^1641261840 is an apocalyptic number.

1641261840 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 1641261840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2616261120).

1641261840 is an abundant number, since it is smaller than the sum of its proper divisors (3591260400).

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

1641261840 is a wasteful number, since it uses less digits than its factorization.

1641261840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861 (or 855 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 1641261840 is about 40512.4899259475. The cubic root of 1641261840 is about 1179.5760806069.

The spelling of 1641261840 in words is "one billion, six hundred forty-one million, two hundred sixty-one thousand, eight hundred forty".