1721421401 has 6 divisors (see below), whose sum is σ = 2002469850. Its totient is φ = 1475504016.

The previous prime is 1721421391. The next prime is 1721421409. The reversal of 1721421401 is 1041241271.

It can be written as a sum of positive squares in only one way, i.e., 1503888400 + 217533001 = 38780^2 + 14749^2 .

It is not a de Polignac number, because 1721421401 - 2³⁰ = 647679577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1721421409) 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, 17565476 + ... + 17565573.

It is an arithmetic number, because the mean of its divisors is an integer number (333744975).

Almost surely, 2^1721421401 is an apocalyptic number.

It is an amenable number.

1721421401 is a deficient number, since it is larger than the sum of its proper divisors (281048449).

1721421401 is an equidigital number, since it uses as much as digits as its factorization.

1721421401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35131063 (or 35131056 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 1721421401 is about 41490.0156784738. The cubic root of 1721421401 is about 1198.4752395660.

Adding to 1721421401 its reverse (1041241271), we get a palindrome (2762662672).

The spelling of 1721421401 in words is "one billion, seven hundred twenty-one million, four hundred twenty-one thousand, four hundred one".