55557021 has 8 divisors (see below), whose sum is σ = 79774240. Its totient is φ = 34188912.

The previous prime is 55557013. The next prime is 55557023. The reversal of 55557021 is 12075555.

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

It is not a de Polignac number, because 55557021 - 2³ = 55557013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 55557021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55557023) 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, 712231 + ... + 712308.

It is an arithmetic number, because the mean of its divisors is an integer number (9971780).

Almost surely, 2^55557021 is an apocalyptic number.

It is an amenable number.

55557021 is a deficient number, since it is larger than the sum of its proper divisors (24217219).

55557021 is a wasteful number, since it uses less digits than its factorization.

55557021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1424555.

The product of its (nonzero) digits is 8750, while the sum is 30.

The square root of 55557021 is about 7453.6582293529. The cubic root of 55557021 is about 381.5747691852.

The spelling of 55557021 in words is "fifty-five million, five hundred fifty-seven thousand, twenty-one".