21510141561 has 24 divisors (see below), whose sum is σ = 31219462560. Its totient is φ = 14271356736.

The previous prime is 21510141557. The next prime is 21510141613. The reversal of 21510141561 is 16514101512.

21510141561 is a `hidden beast` number, since 2 + 1 + 510 + 141 + 5 + 6 + 1 = 666.

It is not a de Polignac number, because 21510141561 - 2² = 21510141557 is a prime.

It is a super-3 number, since 3×21510141561³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21510141061) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1850610 + ... + 1862196.

It is an arithmetic number, because the mean of its divisors is an integer number (1300810940).

Almost surely, 2^21510141561 is an apocalyptic number.

It is an amenable number.

21510141561 is a deficient number, since it is larger than the sum of its proper divisors (9709320999).

21510141561 is a wasteful number, since it uses less digits than its factorization.

21510141561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12565 (or 12562 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 27.

The spelling of 21510141561 in words is "twenty-one billion, five hundred ten million, one hundred forty-one thousand, five hundred sixty-one".