20190397 has 4 divisors (see below), whose sum is σ = 20375740. Its totient is φ = 20005056.

The previous prime is 20190371. The next prime is 20190421. The reversal of 20190397 is 79309102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79309102 = 2 ⋅39654551.

It can be written as a sum of positive squares in 2 ways, for example, as 13461561 + 6728836 = 3669^2 + 2594^2 .

It is a cyclic number.

It is not a de Polignac number, because 20190397 - 2¹⁹ = 19666109 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 (20190347) 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, 92508 + ... + 92725.

It is an arithmetic number, because the mean of its divisors is an integer number (5093935).

Almost surely, 2^20190397 is an apocalyptic number.

It is an amenable number.

20190397 is a deficient number, since it is larger than the sum of its proper divisors (185343).

20190397 is a wasteful number, since it uses less digits than its factorization.

20190397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185342.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 20190397 is about 4493.3725641215. The cubic root of 20190397 is about 272.3004042983.

Adding to 20190397 its reverse (79309102), we get a palindrome (99499499).

The spelling of 20190397 in words is "twenty million, one hundred ninety thousand, three hundred ninety-seven".