90781309805 has 8 divisors (see below), whose sum is σ = 108939845400. Its totient is φ = 72623532096.

The previous prime is 90781309783. The next prime is 90781309807. The reversal of 90781309805 is 50890318709.

It can be written as a sum of positive squares in 4 ways, for example, as 8354325604 + 82426984201 = 91402^2 + 287101^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 90781309805 - 2¹⁸ = 90781047661 is a prime.

It is a super-2 number, since 2×90781309805² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90781309807) 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, 120011 + ... + 442679.

It is an arithmetic number, because the mean of its divisors is an integer number (13617480675).

Almost surely, 2^90781309805 is an apocalyptic number.

It is an amenable number.

90781309805 is a deficient number, since it is larger than the sum of its proper divisors (18158535595).

90781309805 is a wasteful number, since it uses less digits than its factorization.

90781309805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378943.

The product of its (nonzero) digits is 544320, while the sum is 50.

The spelling of 90781309805 in words is "ninety billion, seven hundred eighty-one million, three hundred nine thousand, eight hundred five".