51642779 has 4 divisors (see below), whose sum is σ = 54360840. Its totient is φ = 48924720.

The previous prime is 51642763. The next prime is 51642791. The reversal of 51642779 is 97724615.

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 51642779 - 2⁴ = 51642763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51642079) 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, 1359002 + ... + 1359039.

It is an arithmetic number, because the mean of its divisors is an integer number (13590210).

Almost surely, 2^51642779 is an apocalyptic number.

51642779 is a deficient number, since it is larger than the sum of its proper divisors (2718061).

51642779 is a wasteful number, since it uses less digits than its factorization.

51642779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2718060.

The product of its digits is 105840, while the sum is 41.

The square root of 51642779 is about 7186.2910461517. The cubic root of 51642779 is about 372.3944514251.

The spelling of 51642779 in words is "fifty-one million, six hundred forty-two thousand, seven hundred seventy-nine".