55621261 has 2 divisors, whose sum is σ = 55621262. Its totient is φ = 55621260.

The previous prime is 55621259. The next prime is 55621277. The reversal of 55621261 is 16212655.

55621261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47527236 + 8094025 = 6894^2 + 2845^2 .

It is a cyclic number.

It is not a de Polignac number, because 55621261 - 2¹ = 55621259 is a prime.

Together with 55621259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55621201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27810630 + 27810631.

It is an arithmetic number, because the mean of its divisors is an integer number (27810631).

Almost surely, 2^55621261 is an apocalyptic number.

It is an amenable number.

55621261 is a deficient number, since it is larger than the sum of its proper divisors (1).

55621261 is an equidigital number, since it uses as much as digits as its factorization.

55621261 is an odious number, because the sum of its binary digits is odd.

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

The square root of 55621261 is about 7457.9662777462. The cubic root of 55621261 is about 381.7217828359.

The spelling of 55621261 in words is "fifty-five million, six hundred twenty-one thousand, two hundred sixty-one".