55615421 has 4 divisors (see below), whose sum is σ = 55658844. Its totient is φ = 55572000.

The previous prime is 55615409. The next prime is 55615423. The reversal of 55615421 is 12451655.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47803396 + 7812025 = 6914^2 + 2795^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55615421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55615423) 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, 19730 + ... + 22371.

It is an arithmetic number, because the mean of its divisors is an integer number (13914711).

Almost surely, 2^55615421 is an apocalyptic number.

It is an amenable number.

55615421 is a deficient number, since it is larger than the sum of its proper divisors (43423).

55615421 is a wasteful number, since it uses less digits than its factorization.

55615421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43422.

The product of its digits is 6000, while the sum is 29.

The square root of 55615421 is about 7457.5747398199. The cubic root of 55615421 is about 381.7084226376.

The spelling of 55615421 in words is "fifty-five million, six hundred fifteen thousand, four hundred twenty-one".