20121345 has 32 divisors (see below), whose sum is σ = 36115200. Its totient is φ = 10628352.

The previous prime is 20121337. The next prime is 20121347. The reversal of 20121345 is 54312102.

It is not a de Polignac number, because 20121345 - 2³ = 20121337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20121347) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14596 + ... + 15914.

It is an arithmetic number, because the mean of its divisors is an integer number (1128600).

Almost surely, 2^20121345 is an apocalyptic number.

It is an amenable number.

20121345 is a deficient number, since it is larger than the sum of its proper divisors (15993855).

20121345 is a wasteful number, since it uses less digits than its factorization.

20121345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1446 (or 1440 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20121345 is about 4485.6822223604. The cubic root of 20121345 is about 271.9896234868.

Adding to 20121345 its reverse (54312102), we get a palindrome (74433447).

The spelling of 20121345 in words is "twenty million, one hundred twenty-one thousand, three hundred forty-five".