51236640 has 576 divisors, whose sum is σ = 237758976. Its totient is φ = 9732096.

The previous prime is 51236609. The next prime is 51236641. The reversal of 51236640 is 4663215.

51236640 is a `hidden beast` number, since 5 + 12 + 3 + 6 + 640 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51236641) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2227669 + ... + 2227691.

It is an arithmetic number, because the mean of its divisors is an integer number (412776).

Almost surely, 2^51236640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51236640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118879488).

51236640 is an abundant number, since it is smaller than the sum of its proper divisors (186522336).

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

51236640 is a wasteful number, since it uses less digits than its factorization.

51236640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 51236640 is about 7157.9773679441. The cubic root of 51236640 is about 371.4156625550.

Adding to 51236640 its reverse (4663215), we get a palindrome (55899855).

The spelling of 51236640 in words is "fifty-one million, two hundred thirty-six thousand, six hundred forty".