4642891821 has 6 divisors (see below), whose sum is σ = 6706399310. Its totient is φ = 3095261208.

The previous prime is 4642891819. The next prime is 4642891823. The reversal of 4642891821 is 1281982464.

4642891821 is a `hidden beast` number, since 46 + 428 + 9 + 182 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (4642891819) and next prime (4642891823).

It can be written as a sum of positive squares in only one way, i.e., 4544108100 + 98783721 = 67410^2 + 9939^2 .

It is not a de Polignac number, because 4642891821 - 2¹ = 4642891819 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4642891823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 257938426 + ... + 257938443.

Almost surely, 2^4642891821 is an apocalyptic number.

It is an amenable number.

4642891821 is a deficient number, since it is larger than the sum of its proper divisors (2063507489).

4642891821 is a wasteful number, since it uses less digits than its factorization.

4642891821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515876875 (or 515876872 counting only the distinct ones).

The product of its digits is 221184, while the sum is 45.

The square root of 4642891821 is about 68138.7688544488. The cubic root of 4642891821 is about 1668.2566123924.

The spelling of 4642891821 in words is "four billion, six hundred forty-two million, eight hundred ninety-one thousand, eight hundred twenty-one".