4167721021 has 2 divisors, whose sum is σ = 4167721022. Its totient is φ = 4167721020.

The previous prime is 4167720989. The next prime is 4167721067. The reversal of 4167721021 is 1201277614.

4167721021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4027298521 + 140422500 = 63461^2 + 11850^2 .

It is a cyclic number.

It is not a de Polignac number, because 4167721021 - 2⁵ = 4167720989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4167722021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2083860510 + 2083860511.

It is an arithmetic number, because the mean of its divisors is an integer number (2083860511).

Almost surely, 2^4167721021 is an apocalyptic number.

It is an amenable number.

4167721021 is a deficient number, since it is larger than the sum of its proper divisors (1).

4167721021 is an equidigital number, since it uses as much as digits as its factorization.

4167721021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 4167721021 is about 64557.8889137493. Note that the first 3 decimals coincide. The cubic root of 4167721021 is about 1609.2846919513.

Adding to 4167721021 its reverse (1201277614), we get a palindrome (5368998635).

The spelling of 4167721021 in words is "four billion, one hundred sixty-seven million, seven hundred twenty-one thousand, twenty-one".