19725397 has 4 divisors (see below), whose sum is σ = 19869516. Its totient is φ = 19581280.

The previous prime is 19725379. The next prime is 19725437. The reversal of 19725397 is 79352791.

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 11350161 + 8375236 = 3369^2 + 2894^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19725397 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 (19725317) 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, 71854 + ... + 72127.

It is an arithmetic number, because the mean of its divisors is an integer number (4967379).

Almost surely, 2^19725397 is an apocalyptic number.

It is an amenable number.

19725397 is a deficient number, since it is larger than the sum of its proper divisors (144119).

19725397 is a wasteful number, since it uses less digits than its factorization.

19725397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144118.

The product of its digits is 119070, while the sum is 43.

The square root of 19725397 is about 4441.3282923018. The cubic root of 19725397 is about 270.1937201438.

The spelling of 19725397 in words is "nineteen million, seven hundred twenty-five thousand, three hundred ninety-seven".