20115221 has 8 divisors (see below), whose sum is σ = 23029824. Its totient is φ = 17210880.

The previous prime is 20115211. The next prime is 20115247. The reversal of 20115221 is 12251102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20115221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20115196 and 20115205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20115211) 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, 2246 + ... + 6728.

It is an arithmetic number, because the mean of its divisors is an integer number (2878728).

Almost surely, 2^20115221 is an apocalyptic number.

It is an amenable number.

20115221 is a deficient number, since it is larger than the sum of its proper divisors (2914603).

20115221 is an equidigital number, since it uses as much as digits as its factorization.

20115221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5131.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 20115221 is about 4484.9995540691. Note that the first 3 decimals coincide. The cubic root of 20115221 is about 271.9620270303.

Adding to 20115221 its reverse (12251102), we get a palindrome (32366323).

The spelling of 20115221 in words is "twenty million, one hundred fifteen thousand, two hundred twenty-one".