19997405 has 8 divisors (see below), whose sum is σ = 25260000. Its totient is φ = 15155856.

The previous prime is 19997399. The next prime is 19997413. The reversal of 19997405 is 50479991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19997405 - 2⁸ = 19997149 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105155 + ... + 105344.

It is an arithmetic number, because the mean of its divisors is an integer number (3157500).

Almost surely, 2^19997405 is an apocalyptic number.

It is an amenable number.

19997405 is a deficient number, since it is larger than the sum of its proper divisors (5262595).

19997405 is a wasteful number, since it uses less digits than its factorization.

19997405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210523.

The product of its (nonzero) digits is 102060, while the sum is 44.

The square root of 19997405 is about 4471.8458157678. The cubic root of 19997405 is about 271.4300212955.

It can be divided in two parts, 19997 and 405, that added together give a palindrome (20402).

The spelling of 19997405 in words is "nineteen million, nine hundred ninety-seven thousand, four hundred five".