18278397 has 24 divisors (see below), whose sum is σ = 27428544. Its totient is φ = 11721024.

The previous prime is 18278371. The next prime is 18278401. The reversal of 18278397 is 79387281.

It is not a de Polignac number, because 18278397 - 2¹² = 18274301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18278357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27928 + ... + 28574.

It is an arithmetic number, because the mean of its divisors is an integer number (1142856).

Almost surely, 2^18278397 is an apocalyptic number.

It is an amenable number.

18278397 is a deficient number, since it is larger than the sum of its proper divisors (9150147).

18278397 is a wasteful number, since it uses less digits than its factorization.

18278397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769 (or 766 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 18278397 is about 4275.3241982334. The cubic root of 18278397 is about 263.4183561736.

The spelling of 18278397 in words is "eighteen million, two hundred seventy-eight thousand, three hundred ninety-seven".