73731781 has 8 divisors (see below), whose sum is σ = 74461464. Its totient is φ = 73006080.

The previous prime is 73731731. The next prime is 73731809. The reversal of 73731781 is 18713737.

73731781 = T₃₉ + T₄₀ + ... + T₇₆₁.

It can be written as a sum of positive squares in 4 ways, for example, as 24591681 + 49140100 = 4959^2 + 7010^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 73731781 - 2¹⁹ = 73207493 is a prime.

It is a super-2 number, since 2×73731781² = 10872751058863922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 73731781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73731731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46701 + ... + 48253.

It is an arithmetic number, because the mean of its divisors is an integer number (9307683).

Almost surely, 2^73731781 is an apocalyptic number.

It is an amenable number.

73731781 is a deficient number, since it is larger than the sum of its proper divisors (729683).

73731781 is a wasteful number, since it uses less digits than its factorization.

73731781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1991.

The product of its digits is 24696, while the sum is 37.

The square root of 73731781 is about 8586.7212019490. The cubic root of 73731781 is about 419.3257909364.

The spelling of 73731781 in words is "seventy-three million, seven hundred thirty-one thousand, seven hundred eighty-one".