73815021 has 18 divisors (see below), whose sum is σ = 124030062. Its totient is φ = 42179760.

The previous prime is 73815017. The next prime is 73815023. The reversal of 73815021 is 12051837.

It can be written as a sum of positive squares in only one way, i.e., 73770921 + 44100 = 8589^2 + 210^2 .

It is not a de Polignac number, because 73815021 - 2² = 73815017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73815023) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 83250 + ... + 84131.

It is an arithmetic number, because the mean of its divisors is an integer number (6890559).

Almost surely, 2^73815021 is an apocalyptic number.

It is an amenable number.

73815021 is a deficient number, since it is larger than the sum of its proper divisors (50215041).

73815021 is a wasteful number, since it uses less digits than its factorization.

73815021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167401 (or 167391 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 73815021 is about 8591.5668536071. The cubic root of 73815021 is about 419.4835318333.

Adding to 73815021 its reverse (12051837), we get a palindrome (85866858).

The spelling of 73815021 in words is "seventy-three million, eight hundred fifteen thousand, twenty-one".