646662222401 has 4 divisors (see below), whose sum is σ = 696405470292. Its totient is φ = 596918974512.

The previous prime is 646662222397. The next prime is 646662222449. The reversal of 646662222401 is 104222266646.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 104222266646 = 2 ⋅52111133323.

It can be written as a sum of positive squares in 2 ways, for example, as 86200372801 + 560461849600 = 293599^2 + 748640^2 .

It is a cyclic number.

It is not a de Polignac number, because 646662222401 - 2² = 646662222397 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646662222601) 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, 24871623926 + ... + 24871623951.

It is an arithmetic number, because the mean of its divisors is an integer number (174101367573).

Almost surely, 2^646662222401 is an apocalyptic number.

It is an amenable number.

646662222401 is a deficient number, since it is larger than the sum of its proper divisors (49743247891).

646662222401 is a wasteful number, since it uses less digits than its factorization.

646662222401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49743247890.

The product of its (nonzero) digits is 331776, while the sum is 41.

The spelling of 646662222401 in words is "six hundred forty-six billion, six hundred sixty-two million, two hundred twenty-two thousand, four hundred one".