21474731491 has 2 divisors, whose sum is σ = 21474731492. Its totient is φ = 21474731490.

The previous prime is 21474731479. The next prime is 21474731521. The reversal of 21474731491 is 19413747412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21474731491 - 2⁷ = 21474731363 is a prime.

It is a super-3 number, since 3×21474731491³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21474761491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10737365745 + 10737365746.

It is an arithmetic number, because the mean of its divisors is an integer number (10737365746).

Almost surely, 2^21474731491 is an apocalyptic number.

21474731491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21474731491 is an equidigital number, since it uses as much as digits as its factorization.

21474731491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 43.

The spelling of 21474731491 in words is "twenty-one billion, four hundred seventy-four million, seven hundred thirty-one thousand, four hundred ninety-one".