20121575 has 12 divisors (see below), whose sum is σ = 25039320. Its totient is φ = 16040160.

The previous prime is 20121559. The next prime is 20121581. The reversal of 20121575 is 57512102.

It is a happy number.

It is not a de Polignac number, because 20121575 - 2⁴ = 20121559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121575.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6656 + ... + 9194.

It is an arithmetic number, because the mean of its divisors is an integer number (2086610).

Almost surely, 2^20121575 is an apocalyptic number.

20121575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20121575 is a deficient number, since it is larger than the sum of its proper divisors (4917745).

20121575 is a wasteful number, since it uses less digits than its factorization.

20121575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2866 (or 2861 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 20121575 is about 4485.7078594130. The cubic root of 20121575 is about 271.9906598220.

Adding to 20121575 its reverse (57512102), we get a palindrome (77633677).

The spelling of 20121575 in words is "twenty million, one hundred twenty-one thousand, five hundred seventy-five".