21772017 has 8 divisors (see below), whose sum is σ = 32254880. Its totient is φ = 14514660.

The previous prime is 21772001. The next prime is 21772033. The reversal of 21772017 is 71027712.

It is an interprime number because it is at equal distance from previous prime (21772001) and next prime (21772033).

It is not a de Polignac number, because 21772017 - 2⁴ = 21772001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 806371 = 21772017 / (2 + 1 + 7 + 7 + 2 + 0 + 1 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21772057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 403159 + ... + 403212.

It is an arithmetic number, because the mean of its divisors is an integer number (4031860).

Almost surely, 2^21772017 is an apocalyptic number.

21772017 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21772017 is a deficient number, since it is larger than the sum of its proper divisors (10482863).

21772017 is an equidigital number, since it uses as much as digits as its factorization.

21772017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 806380 (or 806374 counting only the distinct ones).

The product of its (nonzero) digits is 1372, while the sum is 27.

The square root of 21772017 is about 4666.0493996528. The cubic root of 21772017 is about 279.2326652107.

Adding to 21772017 its reverse (71027712), we get a palindrome (92799729).

The spelling of 21772017 in words is "twenty-one million, seven hundred seventy-two thousand, seventeen".