20490421 has 8 divisors (see below), whose sum is σ = 23530304. Its totient is φ = 17478720.

The previous prime is 20490419. The next prime is 20490439. The reversal of 20490421 is 12409402.

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

It is not a de Polignac number, because 20490421 - 2¹ = 20490419 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20490392 and 20490401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20490451) 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, 5460 + ... + 8413.

It is an arithmetic number, because the mean of its divisors is an integer number (2941288).

Almost surely, 2^20490421 is an apocalyptic number.

It is an amenable number.

20490421 is a deficient number, since it is larger than the sum of its proper divisors (3039883).

20490421 is a wasteful number, since it uses less digits than its factorization.

20490421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14091.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 20490421 is about 4526.6346218797. The cubic root of 20490421 is about 273.6425489624.

Adding to 20490421 its reverse (12409402), we get a palindrome (32899823).

The spelling of 20490421 in words is "twenty million, four hundred ninety thousand, four hundred twenty-one".