6420266981 has 4 divisors (see below), whose sum is σ = 6420483552. Its totient is φ = 6420050412.

The previous prime is 6420266921. The next prime is 6420267013. The reversal of 6420266981 is 1896620246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6420266981 - 2¹⁴ = 6420250597 is a prime.

It is a super-2 number, since 2×6420266981² = 82439656214637708722, 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 (6420266911) 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, 55115 + ... + 126008.

It is an arithmetic number, because the mean of its divisors is an integer number (1605120888).

Almost surely, 2^6420266981 is an apocalyptic number.

It is an amenable number.

6420266981 is a deficient number, since it is larger than the sum of its proper divisors (216571).

6420266981 is a wasteful number, since it uses less digits than its factorization.

6420266981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216570.

The product of its (nonzero) digits is 248832, while the sum is 44.

The square root of 6420266981 is about 80126.5685088286. The cubic root of 6420266981 is about 1858.5932807020.

The spelling of 6420266981 in words is "six billion, four hundred twenty million, two hundred sixty-six thousand, nine hundred eighty-one".