7724972021 has 4 divisors (see below), whose sum is σ = 8319200652. Its totient is φ = 7130743392.

The previous prime is 7724971997. The next prime is 7724972041. The reversal of 7724972021 is 1202794277.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1202794277 = 97 ⋅12399941.

It can be written as a sum of positive squares in 2 ways, for example, as 978813796 + 6746158225 = 31286^2 + 82135^2 .

It is a cyclic number.

It is not a de Polignac number, because 7724972021 - 2⁶ = 7724971957 is a prime.

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 7724972021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7724972041) 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, 297114296 + ... + 297114321.

It is an arithmetic number, because the mean of its divisors is an integer number (2079800163).

Almost surely, 2^7724972021 is an apocalyptic number.

It is an amenable number.

7724972021 is a deficient number, since it is larger than the sum of its proper divisors (594228631).

7724972021 is a wasteful number, since it uses less digits than its factorization.

7724972021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594228630.

The product of its (nonzero) digits is 98784, while the sum is 41.

The square root of 7724972021 is about 87891.8199891207. The cubic root of 7724972021 is about 1976.8132273556.

The spelling of 7724972021 in words is "seven billion, seven hundred twenty-four million, nine hundred seventy-two thousand, twenty-one".