51693138 has 144 divisors (see below), whose sum is σ = 140849280. Its totient is φ = 13632192.

The previous prime is 51693137. The next prime is 51693139. The reversal of 51693138 is 83139615.

It is a happy number.

51693138 is a `hidden beast` number, since 516 + 9 + 3 + 138 = 666.

It is an interprime number because it is at equal distance from previous prime (51693137) and next prime (51693139).

It is not an unprimeable number, because it can be changed into a prime (51693133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1099831 + ... + 1099877.

It is an arithmetic number, because the mean of its divisors is an integer number (978120).

Almost surely, 2^51693138 is an apocalyptic number.

51693138 is a gapful number since it is divisible by the number (58) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 51693138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70424640).

51693138 is an abundant number, since it is smaller than the sum of its proper divisors (89156142).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51693138 is a wasteful number, since it uses less digits than its factorization.

51693138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141 (or 131 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 51693138 is about 7189.7940165209. The cubic root of 51693138 is about 372.5154578214.

The spelling of 51693138 in words is "fifty-one million, six hundred ninety-three thousand, one hundred thirty-eight".