2177891640 has 96 divisors (see below), whose sum is σ = 7228802880. Its totient is φ = 568409856.

The previous prime is 2177891629. The next prime is 2177891647. The reversal of 2177891640 is 461987712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2177891647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47439 + ... + 81278.

It is an arithmetic number, because the mean of its divisors is an integer number (75300030).

Almost surely, 2^2177891640 is an apocalyptic number.

2177891640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2177891640 is an abundant number, since it is smaller than the sum of its proper divisors (5050911240).

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

2177891640 is a wasteful number, since it uses less digits than its factorization.

2177891640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128781 (or 128774 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The square root of 2177891640 is about 46667.8866031021. The cubic root of 2177891640 is about 1296.2201129339.

The spelling of 2177891640 in words is "two billion, one hundred seventy-seven million, eight hundred ninety-one thousand, six hundred forty".