21506777241220 has 12 divisors (see below), whose sum is σ = 45164232206604. Its totient is φ = 8602710896480.

The previous prime is 21506777241113. The next prime is 21506777241233. The reversal of 21506777241220 is 2214277760512.

It can be written as a sum of positive squares in 2 ways, for example, as 10491600377476 + 11015176863744 = 3239074^2 + 3318912^2 .

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, 537669431011 + ... + 537669431050.

It is an arithmetic number, because the mean of its divisors is an integer number (3763686017217).

Almost surely, 2^{21506777241220} is an apocalyptic number.

21506777241220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21506777241220 is an abundant number, since it is smaller than the sum of its proper divisors (23657454965384).

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

21506777241220 is a wasteful number, since it uses less digits than its factorization.

21506777241220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1075338862070 (or 1075338862068 counting only the distinct ones).

The product of its (nonzero) digits is 658560, while the sum is 46.

The spelling of 21506777241220 in words is "twenty-one trillion, five hundred six billion, seven hundred seventy-seven million, two hundred forty-one thousand, two hundred twenty".