20121156 has 48 divisors (see below), whose sum is σ = 56911680. Its totient is φ = 6096960.

The previous prime is 20121137. The next prime is 20121169. The reversal of 20121156 is 65112102.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7281 + ... + 9656.

It is an arithmetic number, because the mean of its divisors is an integer number (1185660).

Almost surely, 2^20121156 is an apocalyptic number.

It is an amenable number.

20121156 is an abundant number, since it is smaller than the sum of its proper divisors (36790524).

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

20121156 is a wasteful number, since it uses less digits than its factorization.

20121156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16961 (or 16953 counting only the distinct ones).

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

The square root of 20121156 is about 4485.6611552813. The cubic root of 20121156 is about 271.9887718837.

Adding to 20121156 its reverse (65112102), we get a palindrome (85233258).

The spelling of 20121156 in words is "twenty million, one hundred twenty-one thousand, one hundred fifty-six".