6427721 has 2 divisors, whose sum is σ = 6427722. Its totient is φ = 6427720.

The previous prime is 6427709. The next prime is 6427727. The reversal of 6427721 is 1277246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4999696 + 1428025 = 2236^2 + 1195^2 .

It is a cyclic number.

It is not a de Polignac number, because 6427721 - 2⁶ = 6427657 is a prime.

It is a d-powerful number, because it can be written as 6⁴ + 4¹¹ + 2⁹ + 7⁵ + 7⁶ + 2²¹ + 1 .

It is not a weakly prime, because it can be changed into another prime (6427727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3213860 + 3213861.

It is an arithmetic number, because the mean of its divisors is an integer number (3213861).

Almost surely, 2^6427721 is an apocalyptic number.

It is an amenable number.

6427721 is a deficient number, since it is larger than the sum of its proper divisors (1).

6427721 is an equidigital number, since it uses as much as digits as its factorization.

6427721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 29.

The square root of 6427721 is about 2535.2950518628. The cubic root of 6427721 is about 185.9312286706.

The spelling of 6427721 in words is "six million, four hundred twenty-seven thousand, seven hundred twenty-one".