20349979 has 4 divisors (see below), whose sum is σ = 21915376. Its totient is φ = 18784584.

The previous prime is 20349971. The next prime is 20349983. The reversal of 20349979 is 97994302.

20349979 = T₁₀₀₂ + T₁₀₀₃ + ... + T₁₀₄₀.

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

It is not a de Polignac number, because 20349979 - 2³ = 20349971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20349971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 782679 + ... + 782704.

It is an arithmetic number, because the mean of its divisors is an integer number (5478844).

Almost surely, 2^20349979 is an apocalyptic number.

20349979 is a deficient number, since it is larger than the sum of its proper divisors (1565397).

20349979 is a wasteful number, since it uses less digits than its factorization.

20349979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1565396.

The product of its (nonzero) digits is 122472, while the sum is 43.

The square root of 20349979 is about 4511.0950998621. The cubic root of 20349979 is about 273.0159302292.

The spelling of 20349979 in words is "twenty million, three hundred forty-nine thousand, nine hundred seventy-nine".