670881821 has 2 divisors, whose sum is σ = 670881822. Its totient is φ = 670881820.

The previous prime is 670881767. The next prime is 670881839. The reversal of 670881821 is 128188076.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 590976100 + 79905721 = 24310^2 + 8939^2 .

It is a cyclic number.

It is not a de Polignac number, because 670881821 - 2²² = 666687517 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (670181821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335440910 + 335440911.

It is an arithmetic number, because the mean of its divisors is an integer number (335440911).

Almost surely, 2^670881821 is an apocalyptic number.

It is an amenable number.

670881821 is a deficient number, since it is larger than the sum of its proper divisors (1).

670881821 is an equidigital number, since it uses as much as digits as its factorization.

670881821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43008, while the sum is 41.

The square root of 670881821 is about 25901.3864686816. The cubic root of 670881821 is about 875.4177362091.

The spelling of 670881821 in words is "six hundred seventy million, eight hundred eighty-one thousand, eight hundred twenty-one".