70668721 has 4 divisors (see below), whose sum is σ = 70931700. Its totient is φ = 70405744.

The previous prime is 70668701. The next prime is 70668727. The reversal of 70668721 is 12786607.

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 19044496 + 51624225 = 4364^2 + 7185^2 .

It is a cyclic number.

It is not a de Polignac number, because 70668721 - 2⁷ = 70668593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (70668727) 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, 131086 + ... + 131623.

It is an arithmetic number, because the mean of its divisors is an integer number (17732925).

Almost surely, 2^70668721 is an apocalyptic number.

It is an amenable number.

70668721 is a deficient number, since it is larger than the sum of its proper divisors (262979).

70668721 is a wasteful number, since it uses less digits than its factorization.

70668721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262978.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 70668721 is about 8406.4689971474. The cubic root of 70668721 is about 413.4367491117.

The spelling of 70668721 in words is "seventy million, six hundred sixty-eight thousand, seven hundred twenty-one".