700021891 has 4 divisors (see below), whose sum is σ = 700505784. Its totient is φ = 699538000.

The previous prime is 700021879. The next prime is 700021939. The reversal of 700021891 is 198120007.

700021891 = T₁₆₃ + T₁₆₄ + ... + T₁₆₁₃.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-700021891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (700021391) 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, 239770 + ... + 242671.

It is an arithmetic number, because the mean of its divisors is an integer number (175126446).

Almost surely, 2^700021891 is an apocalyptic number.

700021891 is a deficient number, since it is larger than the sum of its proper divisors (483893).

700021891 is a wasteful number, since it uses less digits than its factorization.

700021891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 483892.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 700021891 is about 26457.9268084255. The cubic root of 700021891 is about 887.9132574111.

Adding to 700021891 its reverse (198120007), we get a palindrome (898141898).

The spelling of 700021891 in words is "seven hundred million, twenty-one thousand, eight hundred ninety-one".