70820257 has 4 divisors (see below), whose sum is σ = 72734356. Its totient is φ = 68906160.

The previous prime is 70820231. The next prime is 70820263. The reversal of 70820257 is 75202807.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75202807 = 31 ⋅2425897.

It can be written as a sum of positive squares in 2 ways, for example, as 57744801 + 13075456 = 7599^2 + 3616^2 .

It is a cyclic number.

It is not a de Polignac number, because 70820257 - 2⁷ = 70820129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (70820227) 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, 956994 + ... + 957067.

It is an arithmetic number, because the mean of its divisors is an integer number (18183589).

Almost surely, 2^70820257 is an apocalyptic number.

It is an amenable number.

70820257 is a deficient number, since it is larger than the sum of its proper divisors (1914099).

70820257 is a wasteful number, since it uses less digits than its factorization.

70820257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1914098.

The product of its (nonzero) digits is 7840, while the sum is 31.

The square root of 70820257 is about 8415.4772294862. The cubic root of 70820257 is about 413.7320510159.

The spelling of 70820257 in words is "seventy million, eight hundred twenty thousand, two hundred fifty-seven".