90356212981 has 4 divisors (see below), whose sum is σ = 90364661100. Its totient is φ = 90347764864.

The previous prime is 90356212963. The next prime is 90356212987. The reversal of 90356212981 is 18921265309.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18921265309 = 277 ⋅68307817.

It can be written as a sum of positive squares in 2 ways, for example, as 88809364081 + 1546848900 = 298009^2 + 39330^2 .

It is a cyclic number.

It is not a de Polignac number, because 90356212981 - 2²¹ = 90354115829 is a prime.

It is a super-2 number, since 2×90356212981² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90356212987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4207996 + ... + 4229413.

It is an arithmetic number, because the mean of its divisors is an integer number (22591165275).

Almost surely, 2^90356212981 is an apocalyptic number.

It is an amenable number.

90356212981 is a deficient number, since it is larger than the sum of its proper divisors (8448119).

90356212981 is a wasteful number, since it uses less digits than its factorization.

90356212981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8448118.

The product of its (nonzero) digits is 233280, while the sum is 46.

The spelling of 90356212981 in words is "ninety billion, three hundred fifty-six million, two hundred twelve thousand, nine hundred eighty-one".