68642551 has 4 divisors (see below), whose sum is σ = 68819400. Its totient is φ = 68465704.

The previous prime is 68642543. The next prime is 68642591. The reversal of 68642551 is 15524686.

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

It is a cyclic number.

It is not a de Polignac number, because 68642551 - 2³ = 68642543 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 68642551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68642501) 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, 87841 + ... + 88618.

It is an arithmetic number, because the mean of its divisors is an integer number (17204850).

Almost surely, 2^68642551 is an apocalyptic number.

68642551 is a deficient number, since it is larger than the sum of its proper divisors (176849).

68642551 is a wasteful number, since it uses less digits than its factorization.

68642551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176848.

The product of its digits is 57600, while the sum is 37.

The square root of 68642551 is about 8285.0800237535. The cubic root of 68642551 is about 409.4471052292.

The spelling of 68642551 in words is "sixty-eight million, six hundred forty-two thousand, five hundred fifty-one".