20661075 has 72 divisors (see below), whose sum is σ = 40622400. Its totient is φ = 10380960.

The previous prime is 20661049. The next prime is 20661101. The reversal of 20661075 is 57016602.

It is an interprime number because it is at equal distance from previous prime (20661049) and next prime (20661101).

It is not a de Polignac number, because 20661075 - 2⁷ = 20660947 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 115336 + ... + 115514.

It is an arithmetic number, because the mean of its divisors is an integer number (564200).

Almost surely, 2^20661075 is an apocalyptic number.

20661075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20661075 is the 2430-th nonagonal number.

20661075 is a deficient number, since it is larger than the sum of its proper divisors (19961325).

20661075 is a wasteful number, since it uses less digits than its factorization.

20661075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 20661075 is about 4545.4455227183. The cubic root of 20661075 is about 274.4001249125.

Adding to 20661075 its reverse (57016602), we get a palindrome (77677677).

The spelling of 20661075 in words is "twenty million, six hundred sixty-one thousand, seventy-five".