203864661 has 128 divisors (see below), whose sum is σ = 427929600. Its totient is φ = 92378880.

The previous prime is 203864653. The next prime is 203864729. The reversal of 203864661 is 166468302.

203864661 is a `hidden beast` number, since 2 + 0 + 3 + 8 + 646 + 6 + 1 = 666.

203864661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 203864661 - 2³ = 203864653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203864261) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 513315 + ... + 513711.

It is an arithmetic number, because the mean of its divisors is an integer number (3343200).

Almost surely, 2^203864661 is an apocalyptic number.

203864661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

203864661 is an abundant number, since it is smaller than the sum of its proper divisors (224064939).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

203864661 is a wasteful number, since it uses less digits than its factorization.

With its successor (203864662) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (456).

203864661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 203864661 is about 14278.1182583700. The cubic root of 203864661 is about 588.5463216913.

The spelling of 203864661 in words is "two hundred three million, eight hundred sixty-four thousand, six hundred sixty-one".