7187722981 has 4 divisors (see below), whose sum is σ = 7196742252. Its totient is φ = 7178703712.

The previous prime is 7187722951. The next prime is 7187722991. The reversal of 7187722981 is 1892277817.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1892277817 = 30071 ⋅62927.

It can be written as a sum of positive squares in 2 ways, for example, as 2594272356 + 4593450625 = 50934^2 + 67775^2 .

It is a cyclic number.

It is not a de Polignac number, because 7187722981 - 2²⁹ = 6650852069 is a prime.

It is a super-2 number, since 2×7187722981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7187722951) 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, 4508440 + ... + 4510033.

It is an arithmetic number, because the mean of its divisors is an integer number (1799185563).

Almost surely, 2^7187722981 is an apocalyptic number.

It is an amenable number.

7187722981 is a deficient number, since it is larger than the sum of its proper divisors (9019271).

7187722981 is an equidigital number, since it uses as much as digits as its factorization.

7187722981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9019270.

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

The square root of 7187722981 is about 84780.4398490595. The cubic root of 7187722981 is about 1929.8806141084.

The spelling of 7187722981 in words is "seven billion, one hundred eighty-seven million, seven hundred twenty-two thousand, nine hundred eighty-one".