1640969843 has 16 divisors (see below), whose sum is σ = 1722258720. Its totient is φ = 1561426944.

The previous prime is 1640969833. The next prime is 1640969851. The reversal of 1640969843 is 3489690461.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1640969843 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1640969791 and 1640969800.

It is not an unprimeable number, because it can be changed into a prime (1640969833) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1619405 + ... + 1620417.

It is an arithmetic number, because the mean of its divisors is an integer number (107641170).

Almost surely, 2^1640969843 is an apocalyptic number.

1640969843 is a deficient number, since it is larger than the sum of its proper divisors (81288877).

1640969843 is a wasteful number, since it uses less digits than its factorization.

1640969843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1798.

The product of its (nonzero) digits is 1119744, while the sum is 50.

The square root of 1640969843 is about 40508.8859757955. The cubic root of 1640969843 is about 1179.5061236391.

The spelling of 1640969843 in words is "one billion, six hundred forty million, nine hundred sixty-nine thousand, eight hundred forty-three".