655863998401 has 4 divisors (see below), whose sum is σ = 663233256900. Its totient is φ = 648494739904.

The previous prime is 655863998399. The next prime is 655863998411. The reversal of 655863998401 is 104899368556.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 83087486001 + 572776512400 = 288249^2 + 756820^2 .

It is a cyclic number.

It is not a de Polignac number, because 655863998401 - 2¹ = 655863998399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (655863998411) 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, 3684629116 + ... + 3684629293.

It is an arithmetic number, because the mean of its divisors is an integer number (165808314225).

Almost surely, 2^655863998401 is an apocalyptic number.

It is an amenable number.

655863998401 is a deficient number, since it is larger than the sum of its proper divisors (7369258499).

655863998401 is an equidigital number, since it uses as much as digits as its factorization.

655863998401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7369258498.

The product of its (nonzero) digits is 55987200, while the sum is 64.

The spelling of 655863998401 in words is "six hundred fifty-five billion, eight hundred sixty-three million, nine hundred ninety-eight thousand, four hundred one".