51845640 has 256 divisors, whose sum is σ = 201277440. Its totient is φ = 10368000.

The previous prime is 51845603. The next prime is 51845641. The reversal of 51845640 is 4654815.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (51845641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 286350 + ... + 286530.

It is an arithmetic number, because the mean of its divisors is an integer number (786240).

Almost surely, 2^51845640 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 51845640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100638720).

51845640 is an abundant number, since it is smaller than the sum of its proper divisors (149431800).

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

51845640 is a wasteful number, since it uses less digits than its factorization.

51845640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 33.

The square root of 51845640 is about 7200.3916560143. The cubic root of 51845640 is about 372.8814224396.

The spelling of 51845640 in words is "fifty-one million, eight hundred forty-five thousand, six hundred forty".