51620004 has 72 divisors (see below), whose sum is σ = 141261120. Its totient is φ = 16451424.

The previous prime is 51619999. The next prime is 51620011. The reversal of 51620004 is 40002615.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 21202 + ... + 23510.

It is an arithmetic number, because the mean of its divisors is an integer number (1961960).

Almost surely, 2^51620004 is an apocalyptic number.

51620004 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 51620004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70630560).

51620004 is an abundant number, since it is smaller than the sum of its proper divisors (89641116).

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

51620004 is a wasteful number, since it uses less digits than its factorization.

51620004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2351 (or 2337 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 51620004 is about 7184.7062570435. The cubic root of 51620004 is about 372.3397001067.

Adding to 51620004 its reverse (40002615), we get a palindrome (91622619).

The spelling of 51620004 in words is "fifty-one million, six hundred twenty thousand, four".