21000010123240 has 16 divisors (see below), whose sum is σ = 47250022777380. Its totient is φ = 8400004049280.

The previous prime is 21000010123217. The next prime is 21000010123303. The reversal of 21000010123240 is 4232101000012.

It can be written as a sum of positive squares in 2 ways, for example, as 20884954840036 + 115055283204 = 4570006^2 + 339198^2 .

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, 262500126501 + ... + 262500126580.

Almost surely, 2^{21000010123240} is an apocalyptic number.

21000010123240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000010123240 is an abundant number, since it is smaller than the sum of its proper divisors (26250012654140).

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

21000010123240 is a wasteful number, since it uses less digits than its factorization.

21000010123240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525000253092 (or 525000253088 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21000010123240 its reverse (4232101000012), we get a palindrome (25232111123252).

The spelling of 21000010123240 in words is "twenty-one trillion, ten million, one hundred twenty-three thousand, two hundred forty".