13631220 has 48 divisors (see below), whose sum is σ = 42409920. Its totient is φ = 3634848.

The previous prime is 13631209. The next prime is 13631221. The reversal of 13631220 is 2213631.

13631220 is a `hidden beast` number, since 13 + 631 + 2 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 13631193 and 13631202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13631221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12082 + ... + 13161.

It is an arithmetic number, because the mean of its divisors is an integer number (883540).

Almost surely, 2^13631220 is an apocalyptic number.

13631220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13631220 is an abundant number, since it is smaller than the sum of its proper divisors (28778700).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13631220 is a wasteful number, since it uses less digits than its factorization.

13631220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25261 (or 25253 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 13631220 is about 3692.0482120362. The cubic root of 13631220 is about 238.8791485322.

Adding to 13631220 its reverse (2213631), we get a palindrome (15844851).

The spelling of 13631220 in words is "thirteen million, six hundred thirty-one thousand, two hundred twenty".