7721204545 has 4 divisors (see below), whose sum is σ = 9265445460. Its totient is φ = 6176963632.

The previous prime is 7721204537. The next prime is 7721204567. The reversal of 7721204545 is 5454021277.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5454021277 = 17 ⋅320824781.

It can be written as a sum of positive squares in 2 ways, for example, as 3882286864 + 3838917681 = 62308^2 + 61959^2 .

It is a cyclic number.

It is not a de Polignac number, because 7721204545 - 2³ = 7721204537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 772120450 + ... + 772120459.

It is an arithmetic number, because the mean of its divisors is an integer number (2316361365).

Almost surely, 2^7721204545 is an apocalyptic number.

It is an amenable number.

7721204545 is a deficient number, since it is larger than the sum of its proper divisors (1544240915).

7721204545 is a wasteful number, since it uses less digits than its factorization.

7721204545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1544240914.

The product of its (nonzero) digits is 78400, while the sum is 37.

The square root of 7721204545 is about 87870.3849143726. The cubic root of 7721204545 is about 1976.4918105517.

The spelling of 7721204545 in words is "seven billion, seven hundred twenty-one million, two hundred four thousand, five hundred forty-five".