21533452491 has 16 divisors (see below), whose sum is σ = 28807084800. Its totient is φ = 14307785568.

The previous prime is 21533452487. The next prime is 21533452529. The reversal of 21533452491 is 19425433512.

It is not a de Polignac number, because 21533452491 - 2² = 21533452487 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21533452481) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1696330 + ... + 1708976.

It is an arithmetic number, because the mean of its divisors is an integer number (1800442800).

Almost surely, 2^21533452491 is an apocalyptic number.

21533452491 is a deficient number, since it is larger than the sum of its proper divisors (7273632309).

21533452491 is a wasteful number, since it uses less digits than its factorization.

21533452491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14498.

The product of its digits is 129600, while the sum is 39.

The spelling of 21533452491 in words is "twenty-one billion, five hundred thirty-three million, four hundred fifty-two thousand, four hundred ninety-one".