78391005 has 64 divisors (see below), whose sum is σ = 158865408. Its totient is φ = 32060160.

The previous prime is 78390997. The next prime is 78391007. The reversal of 78391005 is 50019387.

It is not a de Polignac number, because 78391005 - 2³ = 78390997 is a prime.

It is a super-2 number, since 2×78391005² = 12290299329820050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78391007) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 76879 + ... + 77891.

It is an arithmetic number, because the mean of its divisors is an integer number (2482272).

Almost surely, 2^78391005 is an apocalyptic number.

It is an amenable number.

78391005 is an abundant number, since it is smaller than the sum of its proper divisors (80474403).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78391005 is a wasteful number, since it uses less digits than its factorization.

78391005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1106.

The product of its (nonzero) digits is 7560, while the sum is 33.

The square root of 78391005 is about 8853.8694930522. The cubic root of 78391005 is about 427.9786233391.

The spelling of 78391005 in words is "seventy-eight million, three hundred ninety-one thousand, five".