55021512 has 192 divisors, whose sum is σ = 178113600. Its totient is φ = 14031360.

The previous prime is 55021507. The next prime is 55021513. The reversal of 55021512 is 21512055.

It is a super-2 number, since 2×55021512² = 6054733565532288, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (55021513) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 901962 + ... + 902022.

It is an arithmetic number, because the mean of its divisors is an integer number (927675).

Almost surely, 2^55021512 is an apocalyptic number.

55021512 is a gapful number since it is divisible by the number (52) 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 55021512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89056800).

55021512 is an abundant number, since it is smaller than the sum of its proper divisors (123092088).

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

55021512 is a wasteful number, since it uses less digits than its factorization.

55021512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 55021512 is about 7417.6486840508. The cubic root of 55021512 is about 380.3448208942.

Adding to 55021512 its reverse (21512055), we get a palindrome (76533567).

The spelling of 55021512 in words is "fifty-five million, twenty-one thousand, five hundred twelve".