73687561 has 4 divisors (see below), whose sum is σ = 76891392. Its totient is φ = 70483732.

The previous prime is 73687553. The next prime is 73687577. The reversal of 73687561 is 16578637.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16578637 = 41 ⋅404357.

It is a cyclic number.

It is not a de Polignac number, because 73687561 - 2³ = 73687553 is a prime.

It is a super-2 number, since 2×73687561² = 10859713292257442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (73687501) 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, 1601881 + ... + 1601926.

It is an arithmetic number, because the mean of its divisors is an integer number (19222848).

Almost surely, 2^73687561 is an apocalyptic number.

It is an amenable number.

73687561 is a deficient number, since it is larger than the sum of its proper divisors (3203831).

73687561 is a wasteful number, since it uses less digits than its factorization.

73687561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3203830.

The product of its digits is 211680, while the sum is 43.

The square root of 73687561 is about 8584.1459097571. The cubic root of 73687561 is about 419.2419451629.

The spelling of 73687561 in words is "seventy-three million, six hundred eighty-seven thousand, five hundred sixty-one".