78189749 has 16 divisors (see below), whose sum is σ = 90611136. Its totient is φ = 66681600.

The previous prime is 78189743. The next prime is 78189751. The reversal of 78189749 is 94798187.

It is a cyclic number.

It is not a de Polignac number, because 78189749 - 2⁸ = 78189493 is a prime.

It is a super-2 number, since 2×78189749² = 12227273697366002, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78189749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78189743) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85754 + ... + 86660.

It is an arithmetic number, because the mean of its divisors is an integer number (5663196).

Almost surely, 2^78189749 is an apocalyptic number.

It is an amenable number.

78189749 is a deficient number, since it is larger than the sum of its proper divisors (12421387).

78189749 is a wasteful number, since it uses less digits than its factorization.

78189749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1396.

The product of its digits is 1016064, while the sum is 53.

The square root of 78189749 is about 8842.4967627927. The cubic root of 78189749 is about 427.6120545722.

The spelling of 78189749 in words is "seventy-eight million, one hundred eighty-nine thousand, seven hundred forty-nine".