51604220 has 24 divisors (see below), whose sum is σ = 109898208. Its totient is φ = 20350400.

The previous prime is 51604219. The next prime is 51604229. The reversal of 51604220 is 2240615.

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 = 51604192 and 51604201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51604229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16751 + ... + 19590.

It is an arithmetic number, because the mean of its divisors is an integer number (4579092).

Almost surely, 2^51604220 is an apocalyptic number.

It is an amenable number.

51604220 is an abundant number, since it is smaller than the sum of its proper divisors (58293988).

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

51604220 is a wasteful number, since it uses less digits than its factorization.

51604220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36421 (or 36419 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 51604220 is about 7183.6077287112. The cubic root of 51604220 is about 372.3017457706.

Adding to 51604220 its reverse (2240615), we get a palindrome (53844835).

The spelling of 51604220 in words is "fifty-one million, six hundred four thousand, two hundred twenty".