1640204778915 has 96 divisors (see below), whose sum is σ = 2967232020480. Its totient is φ = 869182068096.

The previous prime is 1640204778899. The next prime is 1640204778917. The reversal of 1640204778915 is 5198774020461.

1640204778915 is a `hidden beast` number, since 1 + 64 + 0 + 20 + 477 + 8 + 91 + 5 = 666.

It is not a de Polignac number, because 1640204778915 - 2⁴ = 1640204778899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1640204778917) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 125171254 + ... + 125184356.

It is an arithmetic number, because the mean of its divisors is an integer number (30908666880).

Almost surely, 2^{1640204778915} is an apocalyptic number.

1640204778915 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1640204778915 is a deficient number, since it is larger than the sum of its proper divisors (1327027241565).

1640204778915 is a wasteful number, since it uses less digits than its factorization.

1640204778915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13775 (or 13763 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 54.

The spelling of 1640204778915 in words is "one trillion, six hundred forty billion, two hundred four million, seven hundred seventy-eight thousand, nine hundred fifteen".