73978621 has 4 divisors (see below), whose sum is σ = 74001312. Its totient is φ = 73955932.

The previous prime is 73978601. The next prime is 73978631. The reversal of 73978621 is 12687937.

It is a happy number.

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: 12687937 = 2857 ⋅4441.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-73978621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73978601) 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, 5425 + ... + 13318.

It is an arithmetic number, because the mean of its divisors is an integer number (18500328).

Almost surely, 2^73978621 is an apocalyptic number.

It is an amenable number.

73978621 is a deficient number, since it is larger than the sum of its proper divisors (22691).

73978621 is a wasteful number, since it uses less digits than its factorization.

73978621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22690.

The product of its digits is 127008, while the sum is 43.

The square root of 73978621 is about 8601.0825481447. The cubic root of 73978621 is about 419.7932107502.

The spelling of 73978621 in words is "seventy-three million, nine hundred seventy-eight thousand, six hundred twenty-one".