55130021 has 4 divisors (see below), whose sum is σ = 55254912. Its totient is φ = 55005132.

The previous prime is 55130003. The next prime is 55130051. The reversal of 55130021 is 12003155.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55130021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55130051) 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, 61781 + ... + 62666.

It is an arithmetic number, because the mean of its divisors is an integer number (13813728).

Almost surely, 2^55130021 is an apocalyptic number.

It is an amenable number.

55130021 is a deficient number, since it is larger than the sum of its proper divisors (124891).

55130021 is a wasteful number, since it uses less digits than its factorization.

55130021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124890.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 55130021 is about 7424.9593264879. The cubic root of 55130021 is about 380.5946851988.

Adding to 55130021 its reverse (12003155), we get a palindrome (67133176).

The spelling of 55130021 in words is "fifty-five million, one hundred thirty thousand, twenty-one".