51409721 has 8 divisors (see below), whose sum is σ = 58017600. Its totient is φ = 45124240.

The previous prime is 51409697. The next prime is 51409723. The reversal of 51409721 is 12790415.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51409721 - 2¹⁴ = 51393337 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51409723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80261 + ... + 80898.

It is an arithmetic number, because the mean of its divisors is an integer number (7252200).

Almost surely, 2^51409721 is an apocalyptic number.

It is an amenable number.

51409721 is a deficient number, since it is larger than the sum of its proper divisors (6607879).

51409721 is a wasteful number, since it uses less digits than its factorization.

51409721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161199.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 51409721 is about 7170.0572522121. The cubic root of 51409721 is about 371.8334153156.

The spelling of 51409721 in words is "fifty-one million, four hundred nine thousand, seven hundred twenty-one".