20571421 has 8 divisors (see below), whose sum is σ = 22254624. Its totient is φ = 18902640.

The previous prime is 20571413. The next prime is 20571431. The reversal of 20571421 is 12417502.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20571421 - 2³ = 20571413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20571392 and 20571401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20571401) 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, 535 + ... + 6436.

It is an arithmetic number, because the mean of its divisors is an integer number (2781828).

Almost surely, 2^20571421 is an apocalyptic number.

It is an amenable number.

20571421 is a deficient number, since it is larger than the sum of its proper divisors (1683203).

20571421 is a wasteful number, since it uses less digits than its factorization.

20571421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7211.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 20571421 is about 4535.5728414391. The cubic root of 20571421 is about 274.0026506217.

Adding to 20571421 its reverse (12417502), we get a palindrome (32988923).

The spelling of 20571421 in words is "twenty million, five hundred seventy-one thousand, four hundred twenty-one".