51621624 has 160 divisors (see below), whose sum is σ = 155509200. Its totient is φ = 15966720.

The previous prime is 51621617. The next prime is 51621659. The reversal of 51621624 is 42612615.

51621624 is a `hidden beast` number, since 5 + 16 + 21 + 624 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 770439 + ... + 770505.

Almost surely, 2^51621624 is an apocalyptic number.

51621624 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51621624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77754600).

51621624 is an abundant number, since it is smaller than the sum of its proper divisors (103887576).

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

51621624 is a wasteful number, since it uses less digits than its factorization.

51621624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 142 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 51621624 is about 7184.8189956324. The cubic root of 51621624 is about 372.3435951342.

Subtracting from 51621624 its reverse (42612615), we obtain a palindrome (9009009).

It can be divided in two parts, 5162 and 1624, that added together give a triangular number (6786 = T₁₁₆).

The spelling of 51621624 in words is "fifty-one million, six hundred twenty-one thousand, six hundred twenty-four".