81521420248 has 32 divisors (see below), whose sum is σ = 161517427200. Its totient is φ = 38494973088.

The previous prime is 81521420221. The next prime is 81521420249. The reversal of 81521420248 is 84202412518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81521420249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2789586 + ... + 2818657.

It is an arithmetic number, because the mean of its divisors is an integer number (5047419600).

Almost surely, 2^81521420248 is an apocalyptic number.

It is an amenable number.

81521420248 is a deficient number, since it is larger than the sum of its proper divisors (79996006952).

81521420248 is a wasteful number, since it uses less digits than its factorization.

81521420248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5608351 (or 5608347 counting only the distinct ones).

The product of its (nonzero) digits is 40960, while the sum is 37.

The spelling of 81521420248 in words is "eighty-one billion, five hundred twenty-one million, four hundred twenty thousand, two hundred forty-eight".