21005309462 has 4 divisors (see below), whose sum is σ = 31507964196. Its totient is φ = 10502654730.

The previous prime is 21005309453. The next prime is 21005309473. The reversal of 21005309462 is 26490350012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5251327364 + ... + 5251327367.

It is an arithmetic number, because the mean of its divisors is an integer number (7876991049).

Almost surely, 2^21005309462 is an apocalyptic number.

21005309462 is a deficient number, since it is larger than the sum of its proper divisors (10502654734).

21005309462 is a wasteful number, since it uses less digits than its factorization.

21005309462 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10502654733.

The product of its (nonzero) digits is 12960, while the sum is 32.

Adding to 21005309462 its reverse (26490350012), we get a palindrome (47495659474).

The spelling of 21005309462 in words is "twenty-one billion, five million, three hundred nine thousand, four hundred sixty-two".