8261636021 has 4 divisors (see below), whose sum is σ = 8275247232. Its totient is φ = 8248024812.

The previous prime is 8261636017. The next prime is 8261636023. The reversal of 8261636021 is 1206361628.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8261636021 - 2² = 8261636017 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 (8261636023) 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, 6804695 + ... + 6805908.

It is an arithmetic number, because the mean of its divisors is an integer number (2068811808).

Almost surely, 2^8261636021 is an apocalyptic number.

It is an amenable number.

8261636021 is a deficient number, since it is larger than the sum of its proper divisors (13611211).

8261636021 is a wasteful number, since it uses less digits than its factorization.

8261636021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13611210.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 8261636021 is about 90893.5422403594. The cubic root of 8261636021 is about 2021.5695428991.

Adding to 8261636021 its reverse (1206361628), we get a palindrome (9467997649).

The spelling of 8261636021 in words is "eight billion, two hundred sixty-one million, six hundred thirty-six thousand, twenty-one".