20407779 has 12 divisors (see below), whose sum is σ = 33689136. Its totient is φ = 11661552.

The previous prime is 20407759. The next prime is 20407781. The reversal of 20407779 is 97770402.

It is not a de Polignac number, because 20407779 - 2⁵ = 20407747 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20407759) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 161904 + ... + 162029.

It is an arithmetic number, because the mean of its divisors is an integer number (2807428).

Almost surely, 2^20407779 is an apocalyptic number.

20407779 is a deficient number, since it is larger than the sum of its proper divisors (13281357).

20407779 is a wasteful number, since it uses less digits than its factorization.

20407779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323946 (or 323943 counting only the distinct ones).

The product of its (nonzero) digits is 24696, while the sum is 36.

The square root of 20407779 is about 4517.4969839503. The cubic root of 20407779 is about 273.2741680719.

The spelling of 20407779 in words is "twenty million, four hundred seven thousand, seven hundred seventy-nine".