1520736821 has 2 divisors, whose sum is σ = 1520736822. Its totient is φ = 1520736820.

The previous prime is 1520736779. The next prime is 1520736851. The reversal of 1520736821 is 1286370251.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 882921796 + 637815025 = 29714^2 + 25255^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1520736821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1520736851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 760368410 + 760368411.

It is an arithmetic number, because the mean of its divisors is an integer number (760368411).

Almost surely, 2^1520736821 is an apocalyptic number.

It is an amenable number.

1520736821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1520736821 is an equidigital number, since it uses as much as digits as its factorization.

1520736821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 1520736821 is about 38996.6257642889. The cubic root of 1520736821 is about 1149.9651712199.

The spelling of 1520736821 in words is "one billion, five hundred twenty million, seven hundred thirty-six thousand, eight hundred twenty-one".