21461941087 has 4 divisors (see below), whose sum is σ = 21961056040. Its totient is φ = 20962826136.

The previous prime is 21461941073. The next prime is 21461941103. The reversal of 21461941087 is 78014916412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21461941087 is a prime.

It is a super-2 number, since 2×21461941087² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 499114909 = 21461941087 / (2 + 1 + 4 + 6 + 1 + 9 + 4 + 1 + 0 + 8 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461941687) 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, 249557412 + ... + 249557497.

It is an arithmetic number, because the mean of its divisors is an integer number (5490264010).

Almost surely, 2^21461941087 is an apocalyptic number.

21461941087 is a deficient number, since it is larger than the sum of its proper divisors (499114953).

21461941087 is an equidigital number, since it uses as much as digits as its factorization.

21461941087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499114952.

The product of its (nonzero) digits is 96768, while the sum is 43.

The spelling of 21461941087 in words is "twenty-one billion, four hundred sixty-one million, nine hundred forty-one thousand, eighty-seven".