20661771 has 24 divisors (see below), whose sum is σ = 30252096. Its totient is φ = 12536160.

The previous prime is 20661763. The next prime is 20661803. The reversal of 20661771 is 17716602.

It is a happy number.

It is not a de Polignac number, because 20661771 - 2³ = 20661763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20668771) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41836 + ... + 42326.

It is an arithmetic number, because the mean of its divisors is an integer number (1260504).

Almost surely, 2^20661771 is an apocalyptic number.

20661771 is a deficient number, since it is larger than the sum of its proper divisors (9590325).

20661771 is a wasteful number, since it uses less digits than its factorization.

20661771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603 (or 590 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 20661771 is about 4545.5220822255. The cubic root of 20661771 is about 274.4032060742.

The spelling of 20661771 in words is "twenty million, six hundred sixty-one thousand, seven hundred seventy-one".