20779121 has 4 divisors (see below), whose sum is σ = 22668144. Its totient is φ = 18890100.

The previous prime is 20779091. The next prime is 20779139. The reversal of 20779121 is 12197702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20779121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20779181) 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, 944495 + ... + 944516.

It is an arithmetic number, because the mean of its divisors is an integer number (5667036).

Almost surely, 2^20779121 is an apocalyptic number.

It is an amenable number.

20779121 is a deficient number, since it is larger than the sum of its proper divisors (1889023).

20779121 is a wasteful number, since it uses less digits than its factorization.

20779121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1889022.

The product of its (nonzero) digits is 1764, while the sum is 29.

The square root of 20779121 is about 4558.4121138835. The cubic root of 20779121 is about 274.9217231757.

The spelling of 20779121 in words is "twenty million, seven hundred seventy-nine thousand, one hundred twenty-one".