21151424500 has 24 divisors (see below), whose sum is σ = 46194712200. Its totient is φ = 8460569600.

The previous prime is 21151424447. The next prime is 21151424507. The reversal of 21151424500 is 542415112.

It can be written as a sum of positive squares in 4 ways, for example, as 1985237136 + 19166187364 = 44556^2 + 138442^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21151424507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21150925 + ... + 21151924.

It is an arithmetic number, because the mean of its divisors is an integer number (1924779675).

Almost surely, 2^21151424500 is an apocalyptic number.

21151424500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21151424500 is an abundant number, since it is smaller than the sum of its proper divisors (25043287700).

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

21151424500 is a wasteful number, since it uses less digits than its factorization.

21151424500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42302868 (or 42302856 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21151424500 its reverse (542415112), we get a palindrome (21693839612).

The spelling of 21151424500 in words is "twenty-one billion, one hundred fifty-one million, four hundred twenty-four thousand, five hundred".