51271640 has 128 divisors (see below), whose sum is σ = 139536000. Its totient is φ = 16934400.

The previous prime is 51271639. The next prime is 51271657. The reversal of 51271640 is 4617215.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 507590 + ... + 507690.

It is an arithmetic number, because the mean of its divisors is an integer number (1090125).

Almost surely, 2^51271640 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 51271640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69768000).

51271640 is an abundant number, since it is smaller than the sum of its proper divisors (88264360).

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

51271640 is a wasteful number, since it uses less digits than its factorization.

51271640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 51271640 is about 7160.4217752867. The cubic root of 51271640 is about 371.5002152585.

Adding to 51271640 its reverse (4617215), we get a palindrome (55888855).

The spelling of 51271640 in words is "fifty-one million, two hundred seventy-one thousand, six hundred forty".