21305431510 has 32 divisors (see below), whose sum is σ = 41874084000. Its totient is φ = 7740399360.

The previous prime is 21305431489. The next prime is 21305431513. The reversal of 21305431510 is 1513450312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305431513) 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, 34666 + ... + 209314.

It is an arithmetic number, because the mean of its divisors is an integer number (1308565125).

Almost surely, 2^21305431510 is an apocalyptic number.

21305431510 is a deficient number, since it is larger than the sum of its proper divisors (20568652490).

21305431510 is a wasteful number, since it uses less digits than its factorization.

21305431510 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175776.

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21305431510 its reverse (1513450312), we get a palindrome (22818881822).

The spelling of 21305431510 in words is "twenty-one billion, three hundred five million, four hundred thirty-one thousand, five hundred ten".