55216993 has 4 divisors (see below), whose sum is σ = 59464468. Its totient is φ = 50969520.

The previous prime is 55216991. The next prime is 55216999. The reversal of 55216993 is 39961255.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39961255 = 5 ⋅7992251.

It can be written as a sum of positive squares in 2 ways, for example, as 29084449 + 26132544 = 5393^2 + 5112^2 .

It is a cyclic number.

It is not a de Polignac number, because 55216993 - 2¹ = 55216991 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55216991) 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, 2123718 + ... + 2123743.

It is an arithmetic number, because the mean of its divisors is an integer number (14866117).

Almost surely, 2^55216993 is an apocalyptic number.

It is an amenable number.

55216993 is a deficient number, since it is larger than the sum of its proper divisors (4247475).

55216993 is a wasteful number, since it uses less digits than its factorization.

55216993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4247474.

The product of its digits is 72900, while the sum is 40.

The square root of 55216993 is about 7430.8137508620. The cubic root of 55216993 is about 380.7947195242.

The spelling of 55216993 in words is "fifty-five million, two hundred sixteen thousand, nine hundred ninety-three".