90901820861 has 4 divisors (see below), whose sum is σ = 96248986812. Its totient is φ = 85554654912.

The previous prime is 90901820809. The next prime is 90901820881. The reversal of 90901820861 is 16802810909.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 77947056100 + 12954764761 = 279190^2 + 113819^2 .

It is a cyclic number.

It is not a de Polignac number, because 90901820861 - 2¹⁸ = 90901558717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90901820881) 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, 2673582950 + ... + 2673582983.

It is an arithmetic number, because the mean of its divisors is an integer number (24062246703).

Almost surely, 2^90901820861 is an apocalyptic number.

It is an amenable number.

90901820861 is a deficient number, since it is larger than the sum of its proper divisors (5347165951).

90901820861 is a wasteful number, since it uses less digits than its factorization.

90901820861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5347165950.

The product of its (nonzero) digits is 62208, while the sum is 44.

The spelling of 90901820861 in words is "ninety billion, nine hundred one million, eight hundred twenty thousand, eight hundred sixty-one".