70870021 has 4 divisors (see below), whose sum is σ = 71023552. Its totient is φ = 70716492.

The previous prime is 70870013. The next prime is 70870039. The reversal of 70870021 is 12007807.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 70870021 - 2³ = 70870013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (70870621) 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, 76071 + ... + 76996.

It is an arithmetic number, because the mean of its divisors is an integer number (17755888).

Almost surely, 2^70870021 is an apocalyptic number.

It is an amenable number.

70870021 is a deficient number, since it is larger than the sum of its proper divisors (153531).

70870021 is a wasteful number, since it uses less digits than its factorization.

70870021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153530.

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

The square root of 70870021 is about 8418.4334053314. The cubic root of 70870021 is about 413.8289354482.

Adding to 70870021 its reverse (12007807), we get a palindrome (82877828).

The spelling of 70870021 in words is "seventy million, eight hundred seventy thousand, twenty-one".