20156321 has 8 divisors (see below), whose sum is σ = 21262080. Its totient is φ = 19055088.

The previous prime is 20156317. The next prime is 20156329. The reversal of 20156321 is 12365102.

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 20156321 - 2² = 20156317 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20156293 and 20156302.

It is not an unprimeable number, because it can be changed into a prime (20156329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12080 + ... + 13646.

It is an arithmetic number, because the mean of its divisors is an integer number (2657760).

Almost surely, 2^20156321 is an apocalyptic number.

It is an amenable number.

20156321 is a deficient number, since it is larger than the sum of its proper divisors (1105759).

20156321 is a wasteful number, since it uses less digits than its factorization.

20156321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2263.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 20156321 is about 4489.5791562239. The cubic root of 20156321 is about 272.1471279068.

The spelling of 20156321 in words is "twenty million, one hundred fifty-six thousand, three hundred twenty-one".