21257154508 has 6 divisors (see below), whose sum is σ = 37200020396. Its totient is φ = 10628577252.

The previous prime is 21257154473. The next prime is 21257154539. The reversal of 21257154508 is 80545175212.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2657144310 + ... + 2657144317.

Almost surely, 2^21257154508 is an apocalyptic number.

It is an amenable number.

21257154508 is a deficient number, since it is larger than the sum of its proper divisors (15942865888).

21257154508 is a wasteful number, since it uses less digits than its factorization.

21257154508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5314288631 (or 5314288629 counting only the distinct ones).

The product of its (nonzero) digits is 112000, while the sum is 40.

The spelling of 21257154508 in words is "twenty-one billion, two hundred fifty-seven million, one hundred fifty-four thousand, five hundred eight".