55787621 has 2 divisors, whose sum is σ = 55787622. Its totient is φ = 55787620.

The previous prime is 55787579. The next prime is 55787623. The reversal of 55787621 is 12678755.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55338721 + 448900 = 7439^2 + 670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55787621 is a prime.

It is a super-2 number, since 2×55787621² = 6224517313679282, which contains 22 as substring.

Together with 55787623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55787623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27893810 + 27893811.

It is an arithmetic number, because the mean of its divisors is an integer number (27893811).

Almost surely, 2^55787621 is an apocalyptic number.

It is an amenable number.

55787621 is a deficient number, since it is larger than the sum of its proper divisors (1).

55787621 is an equidigital number, since it uses as much as digits as its factorization.

55787621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 117600, while the sum is 41.

The square root of 55787621 is about 7469.1111251607. Note that the first 4 decimals coincide. The cubic root of 55787621 is about 382.1019733610.

The spelling of 55787621 in words is "fifty-five million, seven hundred eighty-seven thousand, six hundred twenty-one".