51440340 has 48 divisors (see below), whose sum is σ = 164610432. Its totient is φ = 11757696.

The previous prime is 51440327. The next prime is 51440359. The reversal of 51440340 is 4304415.

It is a super-2 number, since 2×51440340² = 5292217158631200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60819 + ... + 61658.

It is an arithmetic number, because the mean of its divisors is an integer number (3429384).

Almost surely, 2^51440340 is an apocalyptic number.

It is an amenable number.

51440340 is an abundant number, since it is smaller than the sum of its proper divisors (113170092).

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

51440340 is a wasteful number, since it uses less digits than its factorization.

51440340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122496 (or 122494 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 51440340 is about 7172.1921335112. The cubic root of 51440340 is about 371.9072204740.

Adding to 51440340 its reverse (4304415), we get a palindrome (55744755).

It can be divided in two parts, 51 and 440340, that added together give a triangular number (440391 = T₉₃₈).

The spelling of 51440340 in words is "fifty-one million, four hundred forty thousand, three hundred forty".