51221456 has 80 divisors (see below), whose sum is σ = 118825728. Its totient is φ = 21081600.

The previous prime is 51221441. The next prime is 51221491. The reversal of 51221456 is 65412215.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139385 + ... + 139751.

Almost surely, 2^51221456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51221456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59412864).

51221456 is an abundant number, since it is smaller than the sum of its proper divisors (67604272).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51221456 is a wasteful number, since it uses less digits than its factorization.

51221456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460 (or 454 counting only the distinct ones).

The product of its digits is 2400, while the sum is 26.

The square root of 51221456 is about 7156.9166545378. The cubic root of 51221456 is about 371.3789692004.

The spelling of 51221456 in words is "fifty-one million, two hundred twenty-one thousand, four hundred fifty-six".