870938021 has 4 divisors (see below), whose sum is σ = 871471692. Its totient is φ = 870404352.

The previous prime is 870937993. The next prime is 870938023. The reversal of 870938021 is 120839078.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120839078 = 2 ⋅60419539.

It can be written as a sum of positive squares in 2 ways, for example, as 137124100 + 733813921 = 11710^2 + 27089^2 .

It is a cyclic number.

It is not a de Polignac number, because 870938021 - 2¹⁴ = 870921637 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 (870938023) 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, 264380 + ... + 267653.

It is an arithmetic number, because the mean of its divisors is an integer number (217867923).

Almost surely, 2^870938021 is an apocalyptic number.

It is an amenable number.

870938021 is a deficient number, since it is larger than the sum of its proper divisors (533671).

870938021 is a wasteful number, since it uses less digits than its factorization.

870938021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533670.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 870938021 is about 29511.6590689172. The cubic root of 870938021 is about 954.9832406624.

The spelling of 870938021 in words is "eight hundred seventy million, nine hundred thirty-eight thousand, twenty-one".