20487921 has 8 divisors (see below), whose sum is σ = 27397344. Its totient is φ = 13618560.

The previous prime is 20487919. The next prime is 20487937. The reversal of 20487921 is 12978402.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20487921 - 2¹ = 20487919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20487721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8800 + ... + 10881.

It is an arithmetic number, because the mean of its divisors is an integer number (3424668).

Almost surely, 2^20487921 is an apocalyptic number.

It is an amenable number.

20487921 is a deficient number, since it is larger than the sum of its proper divisors (6909423).

20487921 is a wasteful number, since it uses less digits than its factorization.

20487921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20031.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 20487921 is about 4526.3584701170. The cubic root of 20487921 is about 273.6314196288.

The spelling of 20487921 in words is "twenty million, four hundred eighty-seven thousand, nine hundred twenty-one".