315749195821 has 4 divisors (see below), whose sum is σ = 317128013500. Its totient is φ = 314370378144.

The previous prime is 315749195807. The next prime is 315749195837. The reversal of 315749195821 is 128591947513.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128591947513 = 18401 ⋅6988313.

It can be written as a sum of positive squares in 2 ways, for example, as 149235416100 + 166513779721 = 386310^2 + 408061^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-315749195821 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 (315749193821) 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, 689408496 + ... + 689408953.

It is an arithmetic number, because the mean of its divisors is an integer number (79282003375).

Almost surely, 2^315749195821 is an apocalyptic number.

It is an amenable number.

315749195821 is a deficient number, since it is larger than the sum of its proper divisors (1378817679).

315749195821 is a wasteful number, since it uses less digits than its factorization.

315749195821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378817678.

The product of its digits is 2721600, while the sum is 55.

The spelling of 315749195821 in words is "three hundred fifteen billion, seven hundred forty-nine million, one hundred ninety-five thousand, eight hundred twenty-one".