51665646 has 16 divisors (see below), whose sum is σ = 106894800. Its totient is φ = 16627968.

The previous prime is 51665609. The next prime is 51665687. The reversal of 51665646 is 64656615.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148291 + ... + 148638.

It is an arithmetic number, because the mean of its divisors is an integer number (6680925).

Almost surely, 2^51665646 is an apocalyptic number.

51665646 is an abundant number, since it is smaller than the sum of its proper divisors (55229154).

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

51665646 is a wasteful number, since it uses less digits than its factorization.

51665646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296963.

The product of its digits is 129600, while the sum is 39.

The square root of 51665646 is about 7187.8818855070. The cubic root of 51665646 is about 372.4494077199.

The spelling of 51665646 in words is "fifty-one million, six hundred sixty-five thousand, six hundred forty-six".