51667640 has 16 divisors (see below), whose sum is σ = 116252280. Its totient is φ = 20667040.

The previous prime is 51667621. The next prime is 51667663. The reversal of 51667640 is 4676615.

It is a self number, because there is not a number n which added to its sum of digits gives 51667640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 645806 + ... + 645885.

Almost surely, 2^51667640 is an apocalyptic number.

It is an amenable number.

51667640 is an abundant number, since it is smaller than the sum of its proper divisors (64584640).

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

51667640 is a wasteful number, since it uses less digits than its factorization.

51667640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1291702 (or 1291698 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 51667640 is about 7188.0205898425. The cubic root of 51667640 is about 372.4541991343.

Subtracting from 51667640 its reverse (4676615), we obtain a square (46991025 = 6855²).

The spelling of 51667640 in words is "fifty-one million, six hundred sixty-seven thousand, six hundred forty".