51242240 has 216 divisors, whose sum is σ = 153790560. Its totient is φ = 16257024.

The previous prime is 51242237. The next prime is 51242273. The reversal of 51242240 is 4224215.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

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, 1191659 + ... + 1191701.

Almost surely, 2^51242240 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 51242240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76895280).

51242240 is an abundant number, since it is smaller than the sum of its proper divisors (102548320).

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

51242240 is a wasteful number, since it uses less digits than its factorization.

51242240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97 (or 76 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 51242240 is about 7158.3685292111. The cubic root of 51242240 is about 371.4291935746.

Adding to 51242240 its reverse (4224215), we get a palindrome (55466455).

The spelling of 51242240 in words is "fifty-one million, two hundred forty-two thousand, two hundred forty".