70728545521 has 2 divisors, whose sum is σ = 70728545522. Its totient is φ = 70728545520.

The previous prime is 70728545501. The next prime is 70728545579. The reversal of 70728545521 is 12554582707.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43942640625 + 26785904896 = 209625^2 + 163664^2 .

It is a cyclic number.

It is not a de Polignac number, because 70728545521 - 2¹⁵ = 70728512753 is a prime.

It is a super-2 number, since 2×70728545521² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (70728545501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35364272760 + 35364272761.

It is an arithmetic number, because the mean of its divisors is an integer number (35364272761).

Almost surely, 2^70728545521 is an apocalyptic number.

It is an amenable number.

70728545521 is a deficient number, since it is larger than the sum of its proper divisors (1).

70728545521 is an equidigital number, since it uses as much as digits as its factorization.

70728545521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 784000, while the sum is 46.

The spelling of 70728545521 in words is "seventy billion, seven hundred twenty-eight million, five hundred forty-five thousand, five hundred twenty-one".