21247356406 has 16 divisors (see below), whose sum is σ = 31969406304. Its totient is φ = 10590911424.

The previous prime is 21247356373. The next prime is 21247356407. The reversal of 21247356406 is 60465374212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21247356407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2676415 + ... + 2684341.

It is an arithmetic number, because the mean of its divisors is an integer number (1998087894).

Almost surely, 2^21247356406 is an apocalyptic number.

21247356406 is a deficient number, since it is larger than the sum of its proper divisors (10722049898).

21247356406 is a wasteful number, since it uses less digits than its factorization.

21247356406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11895.

The product of its (nonzero) digits is 241920, while the sum is 40.

The spelling of 21247356406 in words is "twenty-one billion, two hundred forty-seven million, three hundred fifty-six thousand, four hundred six".