51224420 has 48 divisors (see below), whose sum is σ = 116433408. Its totient is φ = 18817920.

The previous prime is 51224389. The next prime is 51224429. The reversal of 51224420 is 2442215.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 51224392 and 51224401.

It is not an unprimeable number, because it can be changed into a prime (51224429) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70097 + ... + 70823.

It is an arithmetic number, because the mean of its divisors is an integer number (2425696).

Almost surely, 2^51224420 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 51224420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (58216704).

51224420 is an abundant number, since it is smaller than the sum of its proper divisors (65208988).

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

51224420 is a wasteful number, since it uses less digits than its factorization.

51224420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1020 (or 1018 counting only the distinct ones).

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

The square root of 51224420 is about 7157.1237239550. The cubic root of 51224420 is about 371.3861325138.

Adding to 51224420 its reverse (2442215), we get a palindrome (53666635).

The spelling of 51224420 in words is "fifty-one million, two hundred twenty-four thousand, four hundred twenty".