7121572211661 has 8 divisors (see below), whose sum is σ = 9505089263040. Its totient is φ = 4742884984032.

The previous prime is 7121572211597. The next prime is 7121572211777. The reversal of 7121572211661 is 1661122751217.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7121572211661 - 2⁶ = 7121572211597 is a prime.

It is a super-3 number, since 3×7121572211661³ (a number of 40 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7121572211261) 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 7 ways as a sum of consecutive naturals, for example, 1207452496 + ... + 1207458393.

It is an arithmetic number, because the mean of its divisors is an integer number (1188136157880).

Almost surely, 2^{7121572211661} is an apocalyptic number.

It is an amenable number.

7121572211661 is a deficient number, since it is larger than the sum of its proper divisors (2383517051379).

7121572211661 is a wasteful number, since it uses less digits than its factorization.

7121572211661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2414911875.

The product of its digits is 70560, while the sum is 42.

Adding to 7121572211661 its reverse (1661122751217), we get a palindrome (8782694962878).

The spelling of 7121572211661 in words is "seven trillion, one hundred twenty-one billion, five hundred seventy-two million, two hundred eleven thousand, six hundred sixty-one".