721644435474753 has 64 divisors (see below), whose sum is σ = 1133054334720000. Its totient is φ = 399975969254400.

The previous prime is 721644435474751. The next prime is 721644435474757. The reversal of 721644435474753 is 357474534446127.

It is not a de Polignac number, because 721644435474753 - 2¹ = 721644435474751 is a prime.

It is a super-2 number, since 2×721644435474753² (a number of 31 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (721644435474751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 544118478 + ... + 545443128.

It is an arithmetic number, because the mean of its divisors is an integer number (17703973980000).

Almost surely, 2^{721644435474753} is an apocalyptic number.

It is an amenable number.

721644435474753 is a deficient number, since it is larger than the sum of its proper divisors (411409899245247).

721644435474753 is a wasteful number, since it uses less digits than its factorization.

721644435474753 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328902.

The product of its digits is 948326400, while the sum is 66.

The spelling of 721644435474753 in words is "seven hundred twenty-one trillion, six hundred forty-four billion, four hundred thirty-five million, four hundred seventy-four thousand, seven hundred fifty-three".