21487134861 has 6 divisors (see below), whose sum is σ = 31036972590. Its totient is φ = 14324756568.

The previous prime is 21487134859. The next prime is 21487134863. The reversal of 21487134861 is 16843178412.

It is an interprime number because it is at equal distance from previous prime (21487134859) and next prime (21487134863).

It can be written as a sum of positive squares in only one way, i.e., 18165917961 + 3321216900 = 134781^2 + 57630^2 .

It is not a de Polignac number, because 21487134861 - 2¹ = 21487134859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21487134863) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1193729706 + ... + 1193729723.

It is an arithmetic number, because the mean of its divisors is an integer number (5172828765).

Almost surely, 2^21487134861 is an apocalyptic number.

It is an amenable number.

21487134861 is a deficient number, since it is larger than the sum of its proper divisors (9549837729).

21487134861 is a wasteful number, since it uses less digits than its factorization.

21487134861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2387459435 (or 2387459432 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The spelling of 21487134861 in words is "twenty-one billion, four hundred eighty-seven million, one hundred thirty-four thousand, eight hundred sixty-one".