856921007 has 4 divisors (see below), whose sum is σ = 860982456. Its totient is φ = 852859560.

The previous prime is 856921001. The next prime is 856921019. The reversal of 856921007 is 700129658.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 856921007 - 2⁴ = 856920991 is a prime.

It is a super-2 number, since 2×856921007² = 1468627224475788098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856921001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030408 + ... + 2030829.

It is an arithmetic number, because the mean of its divisors is an integer number (215245614).

Almost surely, 2^856921007 is an apocalyptic number.

856921007 is a deficient number, since it is larger than the sum of its proper divisors (4061449).

856921007 is a wasteful number, since it uses less digits than its factorization.

856921007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4061448.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 856921007 is about 29273.2131307788. The cubic root of 856921007 is about 949.8322906166.

The spelling of 856921007 in words is "eight hundred fifty-six million, nine hundred twenty-one thousand, seven".