70643821 has 2 divisors, whose sum is σ = 70643822. Its totient is φ = 70643820.

The previous prime is 70643809. The next prime is 70643849. The reversal of 70643821 is 12834607.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41602500 + 29041321 = 6450^2 + 5389^2 .

It is an emirp because it is prime and its reverse (12834607) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 70643821 - 2¹⁷ = 70512749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (70643801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35321910 + 35321911.

It is an arithmetic number, because the mean of its divisors is an integer number (35321911).

Almost surely, 2^70643821 is an apocalyptic number.

It is an amenable number.

70643821 is a deficient number, since it is larger than the sum of its proper divisors (1).

70643821 is an equidigital number, since it uses as much as digits as its factorization.

70643821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 70643821 is about 8404.9878643577. The cubic root of 70643821 is about 413.3881855028.

The spelling of 70643821 in words is "seventy million, six hundred forty-three thousand, eight hundred twenty-one".