51661401 has 16 divisors (see below), whose sum is σ = 75878400. Its totient is φ = 31003920.

The previous prime is 51661397. The next prime is 51661411. The reversal of 51661401 is 10416615.

It is not a de Polignac number, because 51661401 - 2² = 51661397 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51661411) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 4201 + ... + 10998.

It is an arithmetic number, because the mean of its divisors is an integer number (4742400).

Almost surely, 2^51661401 is an apocalyptic number.

It is an amenable number.

51661401 is a deficient number, since it is larger than the sum of its proper divisors (24216999).

51661401 is a wasteful number, since it uses less digits than its factorization.

51661401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15316.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 51661401 is about 7187.5865907828. The cubic root of 51661401 is about 372.4392069310.

The spelling of 51661401 in words is "fifty-one million, six hundred sixty-one thousand, four hundred one".