6621745667 has 4 divisors (see below), whose sum is σ = 7011260136. Its totient is φ = 6232231200.

The previous prime is 6621745661. The next prime is 6621745699. The reversal of 6621745667 is 7665471266.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7665471266 = 2 ⋅3832735633.

It is a cyclic number.

It is not a de Polignac number, because 6621745667 - 2¹² = 6621741571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6621745661) 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, 194757209 + ... + 194757242.

It is an arithmetic number, because the mean of its divisors is an integer number (1752815034).

Almost surely, 2^6621745667 is an apocalyptic number.

6621745667 is a deficient number, since it is larger than the sum of its proper divisors (389514469).

6621745667 is a wasteful number, since it uses less digits than its factorization.

6621745667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389514468.

The product of its digits is 2540160, while the sum is 50.

The square root of 6621745667 is about 81374.1093161701. The cubic root of 6621745667 is about 1877.8352995803.

The spelling of 6621745667 in words is "six billion, six hundred twenty-one million, seven hundred forty-five thousand, six hundred sixty-seven".