7121664440 has 64 divisors (see below), whose sum is σ = 17591960160. Its totient is φ = 2573176320.

The previous prime is 7121664413. The next prime is 7121664499. The reversal of 7121664440 is 444661217.

It is a self number, because there is not a number n which added to its sum of digits gives 7121664440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17534 + ... + 120626.

Almost surely, 2^7121664440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7121664440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8795980080).

7121664440 is an abundant number, since it is smaller than the sum of its proper divisors (10470295720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

7121664440 is a wasteful number, since it uses less digits than its factorization.

7121664440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103272 (or 103268 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 35.

The square root of 7121664440 is about 84389.9546154636. The cubic root of 7121664440 is about 1923.9502402548.

The spelling of 7121664440 in words is "seven billion, one hundred twenty-one million, six hundred sixty-four thousand, four hundred forty".