20935421 has 4 divisors (see below), whose sum is σ = 22545852. Its totient is φ = 19324992.

The previous prime is 20935417. The next prime is 20935433. The reversal of 20935421 is 12453902.

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 7896100 + 13039321 = 2810^2 + 3611^2 .

It is a cyclic number.

It is not a de Polignac number, because 20935421 - 2² = 20935417 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 (20935441) 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, 805196 + ... + 805221.

It is an arithmetic number, because the mean of its divisors is an integer number (5636463).

Almost surely, 2^20935421 is an apocalyptic number.

It is an amenable number.

20935421 is a deficient number, since it is larger than the sum of its proper divisors (1610431).

20935421 is a wasteful number, since it uses less digits than its factorization.

20935421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1610430.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20935421 is about 4575.5241229831. The cubic root of 20935421 is about 275.6093200014.

The spelling of 20935421 in words is "twenty million, nine hundred thirty-five thousand, four hundred twenty-one".