1640546399 has 4 divisors (see below), whose sum is σ = 1640631600. Its totient is φ = 1640461200.

The previous prime is 1640546387. The next prime is 1640546423. The reversal of 1640546399 is 9936450461.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1640546399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640546309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1502 + ... + 57300.

It is an arithmetic number, because the mean of its divisors is an integer number (410157900).

Almost surely, 2^1640546399 is an apocalyptic number.

1640546399 is a deficient number, since it is larger than the sum of its proper divisors (85201).

1640546399 is an equidigital number, since it uses as much as digits as its factorization.

1640546399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85200.

The product of its (nonzero) digits is 699840, while the sum is 47.

The square root of 1640546399 is about 40503.6590816188. The cubic root of 1640546399 is about 1179.4046597071.

The spelling of 1640546399 in words is "one billion, six hundred forty million, five hundred forty-six thousand, three hundred ninety-nine".