70720081 has 4 divisors (see below), whose sum is σ = 71449252. Its totient is φ = 69990912.

The previous prime is 70720057. The next prime is 70720087. The reversal of 70720081 is 18002707.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51710481 + 19009600 = 7191^2 + 4360^2 .

It is a cyclic number.

It is not a de Polignac number, because 70720081 - 2⁵ = 70720049 is a prime.

It is a super-2 number, since 2×70720081² = 10002659713293122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (70720087) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 364440 + ... + 364633.

It is an arithmetic number, because the mean of its divisors is an integer number (17862313).

Almost surely, 2^70720081 is an apocalyptic number.

It is an amenable number.

70720081 is a deficient number, since it is larger than the sum of its proper divisors (729171).

70720081 is an equidigital number, since it uses as much as digits as its factorization.

70720081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729170.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 70720081 is about 8409.5232326215. The cubic root of 70720081 is about 413.5368828488.

Adding to 70720081 its reverse (18002707), we get a palindrome (88722788).

It can be divided in two parts, 707200 and 81, that added together give a 4-th power (707281 = 29⁴).

The spelling of 70720081 in words is "seventy million, seven hundred twenty thousand, eighty-one".