12904391 has 4 divisors (see below), whose sum is σ = 13349400.
Its totient is φ = 12459384.
The previous prime is 12904373. The next prime is 12904399. The reversal of 12904391 is 19340921.
It is a happy number.
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is not a de Polignac number, because 12904391 - 210 = 12903367 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 444979 = 12904391 / (1 + 2 + 9 + 0 + 4 + 3 + 9 + 1).
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (12904399) 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, 222461 + ... + 222518.
It is an arithmetic number, because the mean of its divisors is an integer number (3337350).
Almost surely, 212904391 is an apocalyptic number.
12904391 is a deficient number, since it is larger than the sum of its proper divisors (445009).
12904391 is an equidigital number, since it uses as much as digits as its factorization.
12904391 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 445008.
The product of its (nonzero) digits is 1944, while the sum is 29.
The square root of 12904391 is about 3592.2682249520.
The cubic root of 12904391 is about 234.5556171243.
Note that the first 3 decimals are identical.
The spelling of 12904391 in words is "twelve million, nine hundred four thousand, three hundred ninety-one".