51221001 has 8 divisors (see below), whose sum is σ = 73548160. Its totient is φ = 31520592.

The previous prime is 51220999. The next prime is 51221057. The reversal of 51221001 is 10012215.

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

It is not a de Polignac number, because 51221001 - 2¹ = 51220999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51221081) 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, 656641 + ... + 656718.

It is an arithmetic number, because the mean of its divisors is an integer number (9193520).

Almost surely, 2^51221001 is an apocalyptic number.

It is an amenable number.

51221001 is a deficient number, since it is larger than the sum of its proper divisors (22327159).

51221001 is a wasteful number, since it uses less digits than its factorization.

51221001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1313375.

The product of its (nonzero) digits is 20, while the sum is 12.

The square root of 51221001 is about 7156.8848670354. The cubic root of 51221001 is about 371.3778695445.

Adding to 51221001 its reverse (10012215), we get a palindrome (61233216).

The spelling of 51221001 in words is "fifty-one million, two hundred twenty-one thousand, one".