20421279 has 6 divisors (see below), whose sum is σ = 29497416. Its totient is φ = 13614180.

The previous prime is 20421277. The next prime is 20421287. The reversal of 20421279 is 97212402.

It is not a de Polignac number, because 20421279 - 2¹ = 20421277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421277) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1134507 + ... + 1134524.

It is an arithmetic number, because the mean of its divisors is an integer number (4916236).

Almost surely, 2^20421279 is an apocalyptic number.

20421279 is a deficient number, since it is larger than the sum of its proper divisors (9076137).

20421279 is a wasteful number, since it uses less digits than its factorization.

20421279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2269037 (or 2269034 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 20421279 is about 4518.9909271872. The cubic root of 20421279 is about 273.3344128783.

It can be divided in two parts, 2042 and 1279, that added together give a triangular number (3321 = T₈₁).

The spelling of 20421279 in words is "twenty million, four hundred twenty-one thousand, two hundred seventy-nine".