21121432040 has 16 divisors (see below), whose sum is σ = 47523222180. Its totient is φ = 8448572800.

The previous prime is 21121431949. The next prime is 21121432051. The reversal of 21121432040 is 4023412112.

It can be written as a sum of positive squares in 2 ways, for example, as 21108021796 + 13410244 = 145286^2 + 3662^2 .

It is a super-2 number, since 2×21121432040² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264017861 + ... + 264017940.

Almost surely, 2^21121432040 is an apocalyptic number.

21121432040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121432040 is an abundant number, since it is smaller than the sum of its proper divisors (26401790140).

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

21121432040 is a wasteful number, since it uses less digits than its factorization.

21121432040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528035812 (or 528035808 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21121432040 its reverse (4023412112), we get a palindrome (25144844152).

The spelling of 21121432040 in words is "twenty-one billion, one hundred twenty-one million, four hundred thirty-two thousand, forty".