21201156 has 24 divisors (see below), whose sum is σ = 54966240. Its totient is φ = 7067016.

The previous prime is 21201137. The next prime is 21201157. The reversal of 21201156 is 65110212.

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

It is not an unprimeable number, because it can be changed into a prime (21201157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98046 + ... + 98261.

It is an arithmetic number, because the mean of its divisors is an integer number (2290260).

Almost surely, 2^21201156 is an apocalyptic number.

It is an amenable number.

21201156 is an abundant number, since it is smaller than the sum of its proper divisors (33765084).

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

21201156 is a wasteful number, since it uses less digits than its factorization.

21201156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196320 (or 196312 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 21201156 is about 4604.4713051555. The cubic root of 21201156 is about 276.7705311551.

Adding to 21201156 its reverse (65110212), we get a palindrome (86311368).

The spelling of 21201156 in words is "twenty-one million, two hundred one thousand, one hundred fifty-six".