78133921 has 8 divisors (see below), whose sum is σ = 86327424. Its totient is φ = 70340160.

The previous prime is 78133897. The next prime is 78133931. The reversal of 78133921 is 12933187.

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 78133921 - 2⁵ = 78133889 is a prime.

It is a super-2 number, since 2×78133921² = 12209819221668482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78133931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 99525 + ... + 100306.

It is an arithmetic number, because the mean of its divisors is an integer number (10790928).

Almost surely, 2^78133921 is an apocalyptic number.

It is an amenable number.

78133921 is a deficient number, since it is larger than the sum of its proper divisors (8193503).

78133921 is a wasteful number, since it uses less digits than its factorization.

78133921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199871.

The product of its digits is 9072, while the sum is 34.

The square root of 78133921 is about 8839.3393983940. The cubic root of 78133921 is about 427.5102577250.

The spelling of 78133921 in words is "seventy-eight million, one hundred thirty-three thousand, nine hundred twenty-one".