78381644 has 24 divisors (see below), whose sum is σ = 149990400. Its totient is φ = 35544080.

The previous prime is 78381613. The next prime is 78381649. The reversal of 78381644 is 44618387.

It is a super-2 number, since 2×78381644² = 12287364232285472, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78381649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19217 + ... + 22935.

It is an arithmetic number, because the mean of its divisors is an integer number (6249600).

Almost surely, 2^78381644 is an apocalyptic number.

It is an amenable number.

78381644 is a deficient number, since it is larger than the sum of its proper divisors (71608756).

78381644 is a wasteful number, since it uses less digits than its factorization.

78381644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4213 (or 4211 counting only the distinct ones).

The product of its digits is 129024, while the sum is 41.

The square root of 78381644 is about 8853.3408383502. The cubic root of 78381644 is about 427.9615870845.

The spelling of 78381644 in words is "seventy-eight million, three hundred eighty-one thousand, six hundred forty-four".