12991405 has 16 divisors (see below), whose sum is σ = 17988480. Its totient is φ = 8822592.

The previous prime is 12991397. The next prime is 12991423. The reversal of 12991405 is 50419921.

It is a cyclic number.

It is not a de Polignac number, because 12991405 - 2³ = 12991397 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2011 + ... + 5479.

It is an arithmetic number, because the mean of its divisors is an integer number (1124280).

Almost surely, 2^12991405 is an apocalyptic number.

It is an amenable number.

12991405 is a deficient number, since it is larger than the sum of its proper divisors (4997075).

12991405 is a wasteful number, since it uses less digits than its factorization.

12991405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3588.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 12991405 is about 3604.3591663429. The cubic root of 12991405 is about 235.0816375485.

It can be divided in two parts, 1299 and 1405, that added together give a square (2704 = 52²).

The spelling of 12991405 in words is "twelve million, nine hundred ninety-one thousand, four hundred five".