74086851721 has 3 divisors (see below), whose sum is σ = 74087123911. Its totient is φ = 74086579532.

The previous prime is 74086851719. The next prime is 74086851737. The reversal of 74086851721 is 12715868047.

The square root of 74086851721 is 272189.

It is a perfect power (a square), and thus also a powerful 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, and also an emirpimes, since its reverse is a distinct semiprime: 12715868047 = 19 ⋅669256213.

It can be written as a sum of positive squares in only one way, i.e., 68847987321 + 5238864400 = 262389^2 + 72380^2 .

It is not a de Polignac number, because 74086851721 - 2¹ = 74086851719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (74086851701) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 136095 + ... + 408283.

Almost surely, 2^74086851721 is an apocalyptic number.

74086851721 is the 272189-th square number.

74086851721 is the 136095-th centered octagonal number.

It is an amenable number.

74086851721 is a deficient number, since it is larger than the sum of its proper divisors (272190).

74086851721 is an frugal number, since it uses more digits than its factorization.

74086851721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544378 (or 272189 counting only the distinct ones).

The product of its (nonzero) digits is 752640, while the sum is 49.

Multiplying 74086851721 by its sum of digits (49), we get a square (3630255734329 = 1905323²).

The spelling of 74086851721 in words is "seventy-four billion, eighty-six million, eight hundred fifty-one thousand, seven hundred twenty-one".