1851687878157 has 24 divisors (see below), whose sum is σ = 2881671005304. Its totient is φ = 1138998749184.

The previous prime is 1851687878123. The next prime is 1851687878177. The reversal of 1851687878157 is 7518787861581.

1851687878157 is a `hidden beast` number, since 18 + 516 + 8 + 7 + 87 + 8 + 15 + 7 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 281330524836 + 1570357353321 = 530406^2 + 1253139^2 .

It is not a de Polignac number, because 1851687878157 - 2¹¹ = 1851687876109 is a prime.

It is a super-2 number, since 2×1851687878157² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1851687878177) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3215448 + ... + 3747329.

It is an arithmetic number, because the mean of its divisors is an integer number (120069625221).

Almost surely, 2^{1851687878157} is an apocalyptic number.

It is an amenable number.

1851687878157 is a deficient number, since it is larger than the sum of its proper divisors (1029983127147).

1851687878157 is a wasteful number, since it uses less digits than its factorization.

1851687878157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6965069 (or 6965066 counting only the distinct ones).

The product of its digits is 210739200, while the sum is 72.

The spelling of 1851687878157 in words is "one trillion, eight hundred fifty-one billion, six hundred eighty-seven million, eight hundred seventy-eight thousand, one hundred fifty-seven".