81437436990 has 1024 divisors, whose sum is σ = 303077376000. Its totient is φ = 15379144704.

The previous prime is 81437436959. The next prime is 81437437009. The reversal of 81437436990 is 9963473418.

It is a happy number.

81437436990 is a `hidden beast` number, since 81 + 43 + 7 + 436 + 9 + 90 = 666.

It is a super-2 number, since 2×81437436990² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 511 ways as a sum of consecutive naturals, for example, 470736544 + ... + 470736716.

It is an arithmetic number, because the mean of its divisors is an integer number (295974000).

Almost surely, 2^81437436990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81437436990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151538688000).

81437436990 is an abundant number, since it is smaller than the sum of its proper divisors (221639939010).

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

81437436990 is a wasteful number, since it uses less digits than its factorization.

81437436990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263 (or 243 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 54.

The spelling of 81437436990 in words is "eighty-one billion, four hundred thirty-seven million, four hundred thirty-six thousand, nine hundred ninety".