21820815263580 has 48 divisors (see below), whose sum is σ = 61098855143424. Its totient is φ = 5818829555520.

The previous prime is 21820815263551. The next prime is 21820815263587. The reversal of 21820815263580 is 8536251802812.

It is a happy number.

It is a super-2 number, since 2×21820815263580² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21820815263587) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4970229 + ... + 8267091.

It is an arithmetic number, because the mean of its divisors is an integer number (1272892815488).

Almost surely, 2^{21820815263580} is an apocalyptic number.

21820815263580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21820815263580 is an abundant number, since it is smaller than the sum of its proper divisors (39278039879844).

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

21820815263580 is a wasteful number, since it uses less digits than its factorization.

21820815263580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3407186 (or 3407184 counting only the distinct ones).

The product of its (nonzero) digits is 1843200, while the sum is 51.

The spelling of 21820815263580 in words is "twenty-one trillion, eight hundred twenty billion, eight hundred fifteen million, two hundred sixty-three thousand, five hundred eighty".