51320040 has 64 divisors (see below), whose sum is σ = 154431360. Its totient is φ = 13643520.

The previous prime is 51320039. The next prime is 51320041. The reversal of 51320040 is 4002315.

It is an interprime number because it is at equal distance from previous prime (51320039) and next prime (51320041).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (51320041) 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, 77310 + ... + 77970.

It is an arithmetic number, because the mean of its divisors is an integer number (2412990).

Almost surely, 2^51320040 is an apocalyptic number.

It is an amenable number.

51320040 is an abundant number, since it is smaller than the sum of its proper divisors (103111320).

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

51320040 is a wasteful number, since it uses less digits than its factorization.

51320040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1322 (or 1318 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 51320040 is about 7163.8006672436. The cubic root of 51320040 is about 371.6170761946.

Adding to 51320040 its reverse (4002315), we get a palindrome (55322355).

The spelling of 51320040 in words is "fifty-one million, three hundred twenty thousand, forty".