73087781 has 4 divisors (see below), whose sum is σ = 78709932. Its totient is φ = 67465632.

The previous prime is 73087769. The next prime is 73087783. The reversal of 73087781 is 18778037.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9247681 + 63840100 = 3041^2 + 7990^2 .

It is a de Polignac number, because none of the positive numbers 2^k-73087781 is a prime.

It is a super-2 number, since 2×73087781² = 10683647463007922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73087783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2811056 + ... + 2811081.

It is an arithmetic number, because the mean of its divisors is an integer number (19677483).

Almost surely, 2^73087781 is an apocalyptic number.

It is an amenable number.

73087781 is a deficient number, since it is larger than the sum of its proper divisors (5622151).

73087781 is a wasteful number, since it uses less digits than its factorization.

73087781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5622150.

The product of its (nonzero) digits is 65856, while the sum is 41.

The square root of 73087781 is about 8549.1391964338. The cubic root of 73087781 is about 418.1013715205.

The spelling of 73087781 in words is "seventy-three million, eighty-seven thousand, seven hundred eighty-one".