20121975 has 18 divisors (see below), whose sum is σ = 36041096. Its totient is φ = 10731600.

The previous prime is 20121973. The next prime is 20121989. The reversal of 20121975 is 57912102.

It is not a de Polignac number, because 20121975 - 2¹ = 20121973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 44491 + ... + 44940.

Almost surely, 2^20121975 is an apocalyptic number.

20121975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20121975 is a deficient number, since it is larger than the sum of its proper divisors (15919121).

20121975 is a wasteful number, since it uses less digits than its factorization.

20121975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89447 (or 89439 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 20121975 is about 4485.7524452426. The cubic root of 20121975 is about 271.9924621253.

The spelling of 20121975 in words is "twenty million, one hundred twenty-one thousand, nine hundred seventy-five".