4181217821 has 4 divisors (see below), whose sum is σ = 4561328544. Its totient is φ = 3801107100.

The previous prime is 4181217811. The next prime is 4181217827. The reversal of 4181217821 is 1287121814.

4181217821 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4181217821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4181217827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190055345 + ... + 190055366.

It is an arithmetic number, because the mean of its divisors is an integer number (1140332136).

Almost surely, 2^4181217821 is an apocalyptic number.

It is an amenable number.

4181217821 is a deficient number, since it is larger than the sum of its proper divisors (380110723).

4181217821 is a wasteful number, since it uses less digits than its factorization.

4181217821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380110722.

The product of its digits is 7168, while the sum is 35.

The square root of 4181217821 is about 64662.3369590057. The cubic root of 4181217821 is about 1611.0199959938.

The spelling of 4181217821 in words is "four billion, one hundred eighty-one million, two hundred seventeen thousand, eight hundred twenty-one".