7091321581 has 4 divisors (see below), whose sum is σ = 7091957664. Its totient is φ = 7090685500.

The previous prime is 7091321561. The next prime is 7091321591. The reversal of 7091321581 is 1851231907.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 7091321581 - 2⁷ = 7091321453 is a prime.

It is a super-2 number, since 2×7091321581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7091321581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7091321551) 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, 301015 + ... + 323716.

It is an arithmetic number, because the mean of its divisors is an integer number (1772989416).

Almost surely, 2^7091321581 is an apocalyptic number.

It is an amenable number.

7091321581 is a deficient number, since it is larger than the sum of its proper divisors (636083).

7091321581 is a wasteful number, since it uses less digits than its factorization.

7091321581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636082.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 7091321581 is about 84209.9850433427. The cubic root of 7091321581 is about 1921.2139296811.

The spelling of 7091321581 in words is "seven billion, ninety-one million, three hundred twenty-one thousand, five hundred eighty-one".