51215421 has 8 divisors (see below), whose sum is σ = 70642080. Its totient is φ = 32966192.

The previous prime is 51215419. The next prime is 51215429. The reversal of 51215421 is 12451215.

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 51215421 - 2¹ = 51215419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51215429) 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, 294255 + ... + 294428.

It is an arithmetic number, because the mean of its divisors is an integer number (8830260).

Almost surely, 2^51215421 is an apocalyptic number.

It is an amenable number.

51215421 is a deficient number, since it is larger than the sum of its proper divisors (19426659).

51215421 is a wasteful number, since it uses less digits than its factorization.

51215421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588715.

The product of its digits is 400, while the sum is 21.

The square root of 51215421 is about 7156.4950220062. The cubic root of 51215421 is about 371.3643831246.

Adding to 51215421 its reverse (12451215), we get a palindrome (63666636).

The spelling of 51215421 in words is "fifty-one million, two hundred fifteen thousand, four hundred twenty-one".