20156397 has 8 divisors (see below), whose sum is σ = 28289760. Its totient is φ = 12730320.

The previous prime is 20156369. The next prime is 20156401. The reversal of 20156397 is 79365102.

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

It is not a de Polignac number, because 20156397 - 2⁶ = 20156333 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20156317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176754 + ... + 176867.

It is an arithmetic number, because the mean of its divisors is an integer number (3536220).

Almost surely, 2^20156397 is an apocalyptic number.

It is an amenable number.

20156397 is a deficient number, since it is larger than the sum of its proper divisors (8133363).

20156397 is a wasteful number, since it uses less digits than its factorization.

20156397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353643.

The product of its (nonzero) digits is 11340, while the sum is 33.

The square root of 20156397 is about 4489.5876202609. The cubic root of 20156397 is about 272.1474699526.

The spelling of 20156397 in words is "twenty million, one hundred fifty-six thousand, three hundred ninety-seven".