20249979 has 8 divisors (see below), whose sum is σ = 27166272. Its totient is φ = 13416840.

The previous prime is 20249969. The next prime is 20250007. The reversal of 20249979 is 97994202.

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

It is not a de Polignac number, because 20249979 - 2⁴ = 20249963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20249979.

It is not an unprimeable number, because it can be changed into a prime (20249969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20217 + ... + 21194.

It is an arithmetic number, because the mean of its divisors is an integer number (3395784).

Almost surely, 2^20249979 is an apocalyptic number.

20249979 is a deficient number, since it is larger than the sum of its proper divisors (6916293).

20249979 is a wasteful number, since it uses less digits than its factorization.

20249979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41577.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 20249979 is about 4499.9976666661. The cubic root of 20249979 is about 272.5679947037.

The spelling of 20249979 in words is "twenty million, two hundred forty-nine thousand, nine hundred seventy-nine".