51620220 has 96 divisors (see below), whose sum is σ = 162254400. Its totient is φ = 13623552.

The previous prime is 51620209. The next prime is 51620227. The reversal of 51620220 is 2202615.

It is a super-2 number, since 2×51620220² = 5329294225696800, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 51620193 and 51620202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51620227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58422 + ... + 59298.

It is an arithmetic number, because the mean of its divisors is an integer number (1690150).

Almost surely, 2^51620220 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 51620220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81127200).

51620220 is an abundant number, since it is smaller than the sum of its proper divisors (110634180).

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

51620220 is a wasteful number, since it uses less digits than its factorization.

51620220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1004 (or 996 counting only the distinct ones).

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

The square root of 51620220 is about 7184.7212889576. The cubic root of 51620220 is about 372.3402194484.

Adding to 51620220 its reverse (2202615), we get a palindrome (53822835).

It can be divided in two parts, 516 and 20220, that added together give a 4-th power (20736 = 12⁴).

The spelling of 51620220 in words is "fifty-one million, six hundred twenty thousand, two hundred twenty".