51221541 has 16 divisors (see below), whose sum is σ = 78994944. Its totient is φ = 28915824.

The previous prime is 51221537. The next prime is 51221543. The reversal of 51221541 is 14512215.

It is not a de Polignac number, because 51221541 - 2² = 51221537 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51221543) 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, 12951 + ... + 16436.

It is an arithmetic number, because the mean of its divisors is an integer number (4937184).

Almost surely, 2^51221541 is an apocalyptic number.

It is an amenable number.

51221541 is a deficient number, since it is larger than the sum of its proper divisors (27773403).

51221541 is a wasteful number, since it uses less digits than its factorization.

51221541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29480.

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

The square root of 51221541 is about 7156.9225928467. The cubic root of 51221541 is about 371.3791746299.

Adding to 51221541 its reverse (14512215), we get a palindrome (65733756).

The spelling of 51221541 in words is "fifty-one million, two hundred twenty-one thousand, five hundred forty-one".