1916663561257 has 4 divisors (see below), whose sum is σ = 1916722748116. Its totient is φ = 1916604374400.

The previous prime is 1916663561251. The next prime is 1916663561261. The reversal of 1916663561257 is 7521653666191.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1181110330521 + 735553230736 = 1086789^2 + 857644^2 .

It is a cyclic number.

It is not a de Polignac number, because 1916663561257 - 2⁷ = 1916663561129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1916663561251) 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, 29544828 + ... + 29609629.

It is an arithmetic number, because the mean of its divisors is an integer number (479180687029).

Almost surely, 2^{1916663561257} is an apocalyptic number.

It is an amenable number.

1916663561257 is a deficient number, since it is larger than the sum of its proper divisors (59186859).

1916663561257 is an equidigital number, since it uses as much as digits as its factorization.

1916663561257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59186858.

The product of its digits is 12247200, while the sum is 58.

The spelling of 1916663561257 in words is "one trillion, nine hundred sixteen billion, six hundred sixty-three million, five hundred sixty-one thousand, two hundred fifty-seven".