21490474751524 has 9 divisors (see below), whose sum is σ = 37608347040411. Its totient is φ = 10745232739980.

The previous prime is 21490474751467. The next prime is 21490474751569. The reversal of 21490474751524 is 42515747409412.

The square root of 21490474751524 is 4635782.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

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 in 2 ways as a sum of consecutive naturals, for example, 8112619 + ... + 10430509.

Almost surely, 2^{21490474751524} is an apocalyptic number.

21490474751524 is the 4635782-nd square number.

It is an amenable number.

21490474751524 is a deficient number, since it is larger than the sum of its proper divisors (16117872288887).

21490474751524 is an frugal number, since it uses more digits than its factorization.

21490474751524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4635786 (or 2317893 counting only the distinct ones).

The product of its (nonzero) digits is 11289600, while the sum is 55.

The spelling of 21490474751524 in words is "twenty-one trillion, four hundred ninety billion, four hundred seventy-four million, seven hundred fifty-one thousand, five hundred twenty-four".