51398220 has 24 divisors (see below), whose sum is σ = 143915184. Its totient is φ = 13706176.

The previous prime is 51398219. The next prime is 51398227. The reversal of 51398220 is 2289315.

51398220 = 1114² + 1115² + ... + 1153².

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (51398227) 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, 428259 + ... + 428378.

It is an arithmetic number, because the mean of its divisors is an integer number (5996466).

Almost surely, 2^51398220 is an apocalyptic number.

It is an amenable number.

51398220 is an abundant number, since it is smaller than the sum of its proper divisors (92516964).

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

51398220 is a wasteful number, since it uses less digits than its factorization.

51398220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856649 (or 856647 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 51398220 is about 7169.2551914407. The cubic root of 51398220 is about 371.8056853133.

The spelling of 51398220 in words is "fifty-one million, three hundred ninety-eight thousand, two hundred twenty".