68621557 has 4 divisors (see below), whose sum is σ = 68864320. Its totient is φ = 68378796.

The previous prime is 68621513. The next prime is 68621563. The reversal of 68621557 is 75512686.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75512686 = 2 ⋅37756343.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68621557 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 (68621057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120957 + ... + 121522.

It is an arithmetic number, because the mean of its divisors is an integer number (17216080).

Almost surely, 2^68621557 is an apocalyptic number.

It is an amenable number.

68621557 is a deficient number, since it is larger than the sum of its proper divisors (242763).

68621557 is a wasteful number, since it uses less digits than its factorization.

68621557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242762.

The product of its digits is 100800, while the sum is 40.

The square root of 68621557 is about 8283.8129505681. The cubic root of 68621557 is about 409.4053584852.

The spelling of 68621557 in words is "sixty-eight million, six hundred twenty-one thousand, five hundred fifty-seven".