20121487 has 4 divisors (see below), whose sum is σ = 20222800. Its totient is φ = 20020176.

The previous prime is 20121467. The next prime is 20121533. The reversal of 20121487 is 78412102.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20121487 - 2¹¹ = 20119439 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 (20121427) 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 3 ways as a sum of consecutive naturals, for example, 50358 + ... + 50755.

It is an arithmetic number, because the mean of its divisors is an integer number (5055700).

Almost surely, 2^20121487 is an apocalyptic number.

20121487 is a deficient number, since it is larger than the sum of its proper divisors (101313).

20121487 is a wasteful number, since it uses less digits than its factorization.

20121487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101312.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 20121487 is about 4485.6980504711. The cubic root of 20121487 is about 271.9902633121.

Adding to 20121487 its reverse (78412102), we get a palindrome (98533589).

The spelling of 20121487 in words is "twenty million, one hundred twenty-one thousand, four hundred eighty-seven".