78324021 has 12 divisors (see below), whose sum is σ = 114174060. Its totient is φ = 51736320.

The previous prime is 78324019. The next prime is 78324031. The reversal of 78324021 is 12042387.

It can be written as a sum of positive squares in 2 ways, for example, as 54908100 + 23415921 = 7410^2 + 4839^2 .

It is not a de Polignac number, because 78324021 - 2¹ = 78324019 is a prime.

It is a super-2 number, since 2×78324021² = 12269304531216882, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78324031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38940 + ... + 40901.

It is an arithmetic number, because the mean of its divisors is an integer number (9514505).

Almost surely, 2^78324021 is an apocalyptic number.

It is an amenable number.

78324021 is a deficient number, since it is larger than the sum of its proper divisors (35850039).

78324021 is a wasteful number, since it uses less digits than its factorization.

78324021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79956 (or 79953 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 78324021 is about 8850.0859317862. The cubic root of 78324021 is about 427.8566880509.

The spelling of 78324021 in words is "seventy-eight million, three hundred twenty-four thousand, twenty-one".