721512131 has 2 divisors, whose sum is σ = 721512132. Its totient is φ = 721512130.

The previous prime is 721512101. The next prime is 721512133. The reversal of 721512131 is 131215127.

It is a strong prime.

It is an emirp because it is prime and its reverse (131215127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721512131 - 2⁶ = 721512067 is a prime.

It is a super-2 number, since 2×721512131² = 1041159510360322322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 721512133, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 721512097 and 721512106.

It is not a weakly prime, because it can be changed into another prime (721512133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360756065 + 360756066.

It is an arithmetic number, because the mean of its divisors is an integer number (360756066).

Almost surely, 2^721512131 is an apocalyptic number.

721512131 is a deficient number, since it is larger than the sum of its proper divisors (1).

721512131 is an equidigital number, since it uses as much as digits as its factorization.

721512131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420, while the sum is 23.

The square root of 721512131 is about 26860.9778489168. The cubic root of 721512131 is about 896.9079615918.

Adding to 721512131 its reverse (131215127), we get a palindrome (852727258).

The spelling of 721512131 in words is "seven hundred twenty-one million, five hundred twelve thousand, one hundred thirty-one".