21545000040040 has 32 divisors (see below), whose sum is σ = 48478946481000. Its totient is φ = 8617520657664.

The previous prime is 21545000039999. The next prime is 21545000040049. The reversal of 21545000040040 is 4004000054512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20144711217796 + 1400288822244 = 4488286^2 + 1183338^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21545000039987 and 21545000040014.

It is not an unprimeable number, because it can be changed into a prime (21545000040049) 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, 14251395 + ... + 15690514.

Almost surely, 2^{21545000040040} is an apocalyptic number.

21545000040040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21545000040040 is an abundant number, since it is smaller than the sum of its proper divisors (26933946440960).

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

21545000040040 is a wasteful number, since it uses less digits than its factorization.

21545000040040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29959909 (or 29959905 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 25.

Adding to 21545000040040 its reverse (4004000054512), we get a palindrome (25549000094552).

The spelling of 21545000040040 in words is "twenty-one trillion, five hundred forty-five billion, forty thousand, forty".