6398712921 has 8 divisors (see below), whose sum is σ = 8545140544. Its totient is φ = 4259046960.

The previous prime is 6398712889. The next prime is 6398712923. The reversal of 6398712921 is 1292178936.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6398712921 - 2⁵ = 6398712889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6398712923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1688206 + ... + 1691991.

It is an arithmetic number, because the mean of its divisors is an integer number (1068142568).

Almost surely, 2^6398712921 is an apocalyptic number.

It is an amenable number.

6398712921 is a deficient number, since it is larger than the sum of its proper divisors (2146427623).

6398712921 is a wasteful number, since it uses less digits than its factorization.

6398712921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3380831.

The product of its digits is 326592, while the sum is 48.

The square root of 6398712921 is about 79991.9553517727. The cubic root of 6398712921 is about 1856.5110648611.

The spelling of 6398712921 in words is "six billion, three hundred ninety-eight million, seven hundred twelve thousand, nine hundred twenty-one".