73553981 has 4 divisors (see below), whose sum is σ = 73994592. Its totient is φ = 73113372.

The previous prime is 73553971. The next prime is 73553989. The reversal of 73553981 is 18935537.

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: 18935537 = 83 ⋅228139.

It is a cyclic number.

It is not a de Polignac number, because 73553981 - 2¹⁸ = 73291837 is a prime.

It is a super-2 number, since 2×73553981² = 10820376241896722, 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 (73553989) 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, 220055 + ... + 220388.

It is an arithmetic number, because the mean of its divisors is an integer number (18498648).

Almost surely, 2^73553981 is an apocalyptic number.

It is an amenable number.

73553981 is a deficient number, since it is larger than the sum of its proper divisors (440611).

73553981 is a wasteful number, since it uses less digits than its factorization.

73553981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440610.

The product of its digits is 113400, while the sum is 41.

The square root of 73553981 is about 8576.3617577619. The cubic root of 73553981 is about 418.9884595337.

The spelling of 73553981 in words is "seventy-three million, five hundred fifty-three thousand, nine hundred eighty-one".