721501541 has 2 divisors, whose sum is σ = 721501542. Its totient is φ = 721501540.

The previous prime is 721501523. The next prime is 721501577. The reversal of 721501541 is 145105127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614296225 + 107205316 = 24785^2 + 10354^2 .

It is an emirp because it is prime and its reverse (145105127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721501541 - 2¹⁰ = 721500517 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721501541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721501511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360750770 + 360750771.

It is an arithmetic number, because the mean of its divisors is an integer number (360750771).

Almost surely, 2^721501541 is an apocalyptic number.

It is an amenable number.

721501541 is a deficient number, since it is larger than the sum of its proper divisors (1).

721501541 is an equidigital number, since it uses as much as digits as its factorization.

721501541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1400, while the sum is 26.

The square root of 721501541 is about 26860.7807220862. The cubic root of 721501541 is about 896.9035734457.

Adding to 721501541 its reverse (145105127), we get a palindrome (866606668).

The spelling of 721501541 in words is "seven hundred twenty-one million, five hundred one thousand, five hundred forty-one".