7129944721 has 9 divisors (see below), whose sum is σ = 7575549499. Its totient is φ = 6709185184.

The previous prime is 7129944713. The next prime is 7129944743. The reversal of 7129944721 is 1274499217.

It is a happy number.

The square root of 7129944721 is 84439.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 5550995025 + 1578949696 = 74505^2 + 39736^2 .

It is not a de Polignac number, because 7129944721 - 2³ = 7129944713 is a prime.

It is a super-2 number, since 2×7129944721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7129944751) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1432980 + ... + 1437946.

Almost surely, 2^7129944721 is an apocalyptic number.

7129944721 is the 84439-th square number.

7129944721 is the 42220-th centered octagonal number.

It is an amenable number.

7129944721 is a deficient number, since it is larger than the sum of its proper divisors (445604778).

7129944721 is an frugal number, since it uses more digits than its factorization.

7129944721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9968 (or 4984 counting only the distinct ones).

The product of its digits is 254016, while the sum is 46.

The cubic root of 7129944721 is about 1924.6956033897.

The spelling of 7129944721 in words is "seven billion, one hundred twenty-nine million, nine hundred forty-four thousand, seven hundred twenty-one".