27528921981 has 32 divisors (see below), whose sum is σ = 44501529600. Its totient is φ = 16680317040.

The previous prime is 27528921919. The next prime is 27528921991. The reversal of 27528921981 is 18912982572.

27528921981 is a `hidden beast` number, since 2 + 7 + 528 + 9 + 21 + 98 + 1 = 666.

It is not a de Polignac number, because 27528921981 - 2¹⁰ = 27528920957 is a prime.

It is a super-2 number, since 2×27528921981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27528921911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1756080 + ... + 1771686.

It is an arithmetic number, because the mean of its divisors is an integer number (1390672800).

Almost surely, 2^27528921981 is an apocalyptic number.

It is an amenable number.

27528921981 is a deficient number, since it is larger than the sum of its proper divisors (16972607619).

27528921981 is a wasteful number, since it uses less digits than its factorization.

27528921981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21566 (or 21560 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 54.

The spelling of 27528921981 in words is "twenty-seven billion, five hundred twenty-eight million, nine hundred twenty-one thousand, nine hundred eighty-one".