18906397 has 4 divisors (see below), whose sum is σ = 20018556. Its totient is φ = 17794240.

The previous prime is 18906383. The next prime is 18906409. The reversal of 18906397 is 79360981.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17480761 + 1425636 = 4181^2 + 1194^2 .

It is not a de Polignac number, because 18906397 - 2¹¹ = 18904349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18906697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 556054 + ... + 556087.

It is an arithmetic number, because the mean of its divisors is an integer number (5004639).

Almost surely, 2^18906397 is an apocalyptic number.

18906397 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18906397 is a deficient number, since it is larger than the sum of its proper divisors (1112159).

18906397 is a wasteful number, since it uses less digits than its factorization.

18906397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1112158.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 18906397 is about 4348.1486865102. The cubic root of 18906397 is about 266.4012496297.

The spelling of 18906397 in words is "eighteen million, nine hundred six thousand, three hundred ninety-seven".