8121379581 has 24 divisors (see below), whose sum is σ = 13659684480. Its totient is φ = 4553224416.

The previous prime is 8121379579. The next prime is 8121379583. The reversal of 8121379581 is 1859731218.

It is an interprime number because it is at equal distance from previous prime (8121379579) and next prime (8121379583).

It is not a de Polignac number, because 8121379581 - 2¹ = 8121379579 is a prime.

It is a super-2 number, since 2×8121379581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8121379583) 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, 1212801 + ... + 1219478.

It is an arithmetic number, because the mean of its divisors is an integer number (569153520).

Almost surely, 2^8121379581 is an apocalyptic number.

It is an amenable number.

8121379581 is a deficient number, since it is larger than the sum of its proper divisors (5538304899).

8121379581 is a wasteful number, since it uses less digits than its factorization.

8121379581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2432345 (or 2432342 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 8121379581 is about 90118.6971776667. The cubic root of 8121379581 is about 2010.0642357135.

The spelling of 8121379581 in words is "eight billion, one hundred twenty-one million, three hundred seventy-nine thousand, five hundred eighty-one".