70240721 has 2 divisors, whose sum is σ = 70240722. Its totient is φ = 70240720.

The previous prime is 70240711. The next prime is 70240757. The reversal of 70240721 is 12704207.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48720400 + 21520321 = 6980^2 + 4639^2 .

It is a cyclic number.

It is not a de Polignac number, because 70240721 - 2⁶ = 70240657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (70240711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35120360 + 35120361.

It is an arithmetic number, because the mean of its divisors is an integer number (35120361).

Almost surely, 2^70240721 is an apocalyptic number.

It is an amenable number.

70240721 is a deficient number, since it is larger than the sum of its proper divisors (1).

70240721 is an equidigital number, since it uses as much as digits as its factorization.

70240721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 70240721 is about 8380.9737501080. The cubic root of 70240721 is about 412.6004084925.

Adding to 70240721 its reverse (12704207), we get a palindrome (82944928).

The spelling of 70240721 in words is "seventy million, two hundred forty thousand, seven hundred twenty-one".