20121291 has 40 divisors (see below), whose sum is σ = 31624560. Its totient is φ = 12737088.

The previous prime is 20121287. The next prime is 20121307. The reversal of 20121291 is 19212102.

It is not a de Polignac number, because 20121291 - 2² = 20121287 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20121271) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 184545 + ... + 184653.

It is an arithmetic number, because the mean of its divisors is an integer number (790614).

Almost surely, 2^20121291 is an apocalyptic number.

20121291 is a deficient number, since it is larger than the sum of its proper divisors (11503269).

20121291 is a wasteful number, since it uses less digits than its factorization.

20121291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217 (or 208 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 20121291 is about 4485.6762032050. The cubic root of 20121291 is about 271.9893801722.

Adding to 20121291 its reverse (19212102), we get a palindrome (39333393).

The spelling of 20121291 in words is "twenty million, one hundred twenty-one thousand, two hundred ninety-one".