156721513493 has 2 divisors, whose sum is σ = 156721513494. Its totient is φ = 156721513492.

The previous prime is 156721513477. The next prime is 156721513513. The reversal of 156721513493 is 394315127651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121579137124 + 35142376369 = 348682^2 + 187463^2 .

It is a cyclic number.

It is not a de Polignac number, because 156721513493 - 2⁴ = 156721513477 is a prime.

It is a super-2 number, since 2×156721513493² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156721515493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78360756746 + 78360756747.

It is an arithmetic number, because the mean of its divisors is an integer number (78360756747).

Almost surely, 2^156721513493 is an apocalyptic number.

It is an amenable number.

156721513493 is a deficient number, since it is larger than the sum of its proper divisors (1).

156721513493 is an equidigital number, since it uses as much as digits as its factorization.

156721513493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 47.

The spelling of 156721513493 in words is "one hundred fifty-six billion, seven hundred twenty-one million, five hundred thirteen thousand, four hundred ninety-three".