20777161 has 4 divisors (see below), whose sum is σ = 21447424. Its totient is φ = 20106900.

The previous prime is 20777101. The next prime is 20777167. The reversal of 20777161 is 16177702.

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 not a de Polignac number, because 20777161 - 2¹⁵ = 20744393 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 670231 = 20777161 / (2 + 0 + 7 + 7 + 7 + 1 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20777167) 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, 335085 + ... + 335146.

It is an arithmetic number, because the mean of its divisors is an integer number (5361856).

Almost surely, 2^20777161 is an apocalyptic number.

It is an amenable number.

20777161 is a deficient number, since it is larger than the sum of its proper divisors (670263).

20777161 is an equidigital number, since it uses as much as digits as its factorization.

20777161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 670262.

The product of its (nonzero) digits is 4116, while the sum is 31.

The square root of 20777161 is about 4558.1971216699. The cubic root of 20777161 is about 274.9130788652.

The spelling of 20777161 in words is "twenty million, seven hundred seventy-seven thousand, one hundred sixty-one".