384215661 has 6 divisors (see below), whose sum is σ = 554978190. Its totient is φ = 256143768.

The previous prime is 384215651. The next prime is 384215677. The reversal of 384215661 is 166512483.

It is a happy number.

384215661 is a `hidden beast` number, since 384 + 215 + 6 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 383768100 + 447561 = 19590^2 + 669^2 .

It is not a de Polignac number, because 384215661 - 2²² = 380021357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (384215641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21345306 + ... + 21345323.

It is an arithmetic number, because the mean of its divisors is an integer number (92496365).

Almost surely, 2^384215661 is an apocalyptic number.

It is an amenable number.

384215661 is a deficient number, since it is larger than the sum of its proper divisors (170762529).

384215661 is a wasteful number, since it uses less digits than its factorization.

384215661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42690635 (or 42690632 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 384215661 is about 19601.4198720399. The cubic root of 384215661 is about 726.9842818219.

It can be divided in two parts, 3842 and 15661, that added together give a triangular number (19503 = T₁₉₇).

The spelling of 384215661 in words is "three hundred eighty-four million, two hundred fifteen thousand, six hundred sixty-one".