73565499721 has 24 divisors (see below), whose sum is σ = 87836865480. Its totient is φ = 61396473600.

The previous prime is 73565499647. The next prime is 73565499757. The reversal of 73565499721 is 12799456537.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 689797696 + 72875702025 = 26264^2 + 269955^2 .

It is not a de Polignac number, because 73565499721 - 2¹³ = 73565491529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (73565499781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 986611 + ... + 1058551.

It is an arithmetic number, because the mean of its divisors is an integer number (3659869395).

Almost surely, 2^73565499721 is an apocalyptic number.

It is an amenable number.

73565499721 is a deficient number, since it is larger than the sum of its proper divisors (14271365759).

73565499721 is a wasteful number, since it uses less digits than its factorization.

73565499721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72505 (or 72498 counting only the distinct ones).

The product of its digits is 14288400, while the sum is 58.

The spelling of 73565499721 in words is "seventy-three billion, five hundred sixty-five million, four hundred ninety-nine thousand, seven hundred twenty-one".