55661421 has 8 divisors (see below), whose sum is σ = 74337984. Its totient is φ = 37046240.

The previous prime is 55661387. The next prime is 55661423. The reversal of 55661421 is 12416655.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55661421 - 2¹⁹ = 55137133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55661423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13185 + ... + 16886.

It is an arithmetic number, because the mean of its divisors is an integer number (9292248).

Almost surely, 2^55661421 is an apocalyptic number.

It is an amenable number.

55661421 is a deficient number, since it is larger than the sum of its proper divisors (18676563).

55661421 is a wasteful number, since it uses less digits than its factorization.

55661421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30691.

The product of its digits is 7200, while the sum is 30.

The square root of 55661421 is about 7460.6582149298. The cubic root of 55661421 is about 381.8136317588.

The spelling of 55661421 in words is "fifty-five million, six hundred sixty-one thousand, four hundred twenty-one".