20125421 has 4 divisors (see below), whose sum is σ = 20143644. Its totient is φ = 20107200.

The previous prime is 20125411. The next prime is 20125439. The reversal of 20125421 is 12452102.

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

It can be written as a sum of positive squares in 2 ways, for example, as 18369796 + 1755625 = 4286^2 + 1325^2 .

It is a cyclic number.

It is not a de Polignac number, because 20125421 - 2¹⁰ = 20124397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20125421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20125411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7340 + ... + 9701.

It is an arithmetic number, because the mean of its divisors is an integer number (5035911).

Almost surely, 2^20125421 is an apocalyptic number.

It is an amenable number.

20125421 is a deficient number, since it is larger than the sum of its proper divisors (18223).

20125421 is a wasteful number, since it uses less digits than its factorization.

20125421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18222.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 20125421 is about 4486.1365338117. The cubic root of 20125421 is about 272.0079879791.

Adding to 20125421 its reverse (12452102), we get a palindrome (32577523).

The spelling of 20125421 in words is "twenty million, one hundred twenty-five thousand, four hundred twenty-one".