551660401 has 2 divisors, whose sum is σ = 551660402. Its totient is φ = 551660400.

The previous prime is 551660399. The next prime is 551660423. The reversal of 551660401 is 104066155.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 439321600 + 112338801 = 20960^2 + 10599^2 .

It is a cyclic number.

It is not a de Polignac number, because 551660401 - 2¹ = 551660399 is a prime.

Together with 551660399, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 551660401.

It is not a weakly prime, because it can be changed into another prime (551661401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275830200 + 275830201.

It is an arithmetic number, because the mean of its divisors is an integer number (275830201).

Almost surely, 2^551660401 is an apocalyptic number.

It is an amenable number.

551660401 is a deficient number, since it is larger than the sum of its proper divisors (1).

551660401 is an equidigital number, since it uses as much as digits as its factorization.

551660401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 551660401 is about 23487.4519903714. The cubic root of 551660401 is about 820.1449282801.

The spelling of 551660401 in words is "five hundred fifty-one million, six hundred sixty thousand, four hundred one".