721451 has 2 divisors, whose sum is σ = 721452. Its totient is φ = 721450.

The previous prime is 721439. The next prime is 721481. The reversal of 721451 is 154127.

It is a weak prime.

It is an emirp because it is prime and its reverse (154127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721451 - 2⁶ = 721387 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (721481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360725 + 360726.

It is an arithmetic number, because the mean of its divisors is an integer number (360726).

2⁷²¹⁴⁵¹ is an apocalyptic number.

721451 is a deficient number, since it is larger than the sum of its proper divisors (1).

721451 is an equidigital number, since it uses as much as digits as its factorization.

721451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 280, while the sum is 20.

The square root of 721451 is about 849.3827170363. The cubic root of 721451 is about 89.6882630334.

Adding to 721451 its reverse (154127), we get a palindrome (875578).

The spelling of 721451 in words is "seven hundred twenty-one thousand, four hundred fifty-one".