1961640 has 48 divisors (see below), whose sum is σ = 6376500. Its totient is φ = 523008.

The previous prime is 1961633. The next prime is 1961651. The reversal of 1961640 is 461691.

1961640 is a `hidden beast` number, since 1 + 9 + 616 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1790244 + 171396 = 1338^2 + 414^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2365 + ... + 3084.

2^1961640 is an apocalyptic number.

1961640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1961640 is an abundant number, since it is smaller than the sum of its proper divisors (4414860).

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

1961640 is a wasteful number, since it uses less digits than its factorization.

1961640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5466 (or 5459 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 1961640 is about 1400.5855918151. The cubic root of 1961640 is about 125.1813899874.

It can be divided in two parts, 1961 and 640, that added together give a square (2601 = 51²).

The spelling of 1961640 in words is "one million, nine hundred sixty-one thousand, six hundred forty".