7087890021721 has 4 divisors (see below), whose sum is σ = 7332300022500. Its totient is φ = 6843480020944.

The previous prime is 7087890021689. The next prime is 7087890021733. The reversal of 7087890021721 is 1271200987807.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4931797185225 + 2156092836496 = 2220765^2 + 1468364^2 .

It is a cyclic number.

It is not a de Polignac number, because 7087890021721 - 2⁵ = 7087890021689 is a prime.

It is a super-3 number, since 3×7087890021721³ (a number of 40 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7087890021221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122205000346 + ... + 122205000403.

It is an arithmetic number, because the mean of its divisors is an integer number (1833075005625).

Almost surely, 2^{7087890021721} is an apocalyptic number.

It is an amenable number.

7087890021721 is a deficient number, since it is larger than the sum of its proper divisors (244410000779).

7087890021721 is a wasteful number, since it uses less digits than its factorization.

7087890021721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244410000778.

The product of its (nonzero) digits is 790272, while the sum is 52.

The spelling of 7087890021721 in words is "seven trillion, eighty-seven billion, eight hundred ninety million, twenty-one thousand, seven hundred twenty-one".