21005309464 has 32 divisors (see below), whose sum is σ = 40759848000. Its totient is φ = 10136315392.

The previous prime is 21005309453. The next prime is 21005309473. The reversal of 21005309464 is 46490350012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 587937 + ... + 622639.

It is an arithmetic number, because the mean of its divisors is an integer number (1273745250).

Almost surely, 2^21005309464 is an apocalyptic number.

It is an amenable number.

21005309464 is a deficient number, since it is larger than the sum of its proper divisors (19754538536).

21005309464 is a wasteful number, since it uses less digits than its factorization.

21005309464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37347 (or 37343 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

Adding to 21005309464 its reverse (46490350012), we get a palindrome (67495659476).

The spelling of 21005309464 in words is "twenty-one billion, five million, three hundred nine thousand, four hundred sixty-four".