51690240 has 216 divisors, whose sum is σ = 204710688. Its totient is φ = 11796480.

The previous prime is 51690179. The next prime is 51690263. The reversal of 51690240 is 4209615.

It is a super-2 number, since 2×51690240² = 5343761822515200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80320 + ... + 80960.

Almost surely, 2^51690240 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 51690240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102355344).

51690240 is an abundant number, since it is smaller than the sum of its proper divisors (153020448).

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

51690240 is a wasteful number, since it uses less digits than its factorization.

51690240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675 (or 658 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 51690240 is about 7189.5924780199. The cubic root of 51690240 is about 372.5084964205.

Adding to 51690240 its reverse (4209615), we get a palindrome (55899855).

The spelling of 51690240 in words is "fifty-one million, six hundred ninety thousand, two hundred forty".