21490387216 has 45 divisors (see below), whose sum is σ = 42345772119. Its totient is φ = 10565466912.

The previous prime is 21490387213. The next prime is 21490387229. The reversal of 21490387216 is 61278309412.

The square root of 21490387216 is 146596.

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

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21490387213) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 39287455 + ... + 39288001.

Almost surely, 2^21490387216 is an apocalyptic number.

21490387216 is the 146596-th square number.

It is an amenable number.

21490387216 is a deficient number, since it is larger than the sum of its proper divisors (20855384903).

21490387216 is an frugal number, since it uses more digits than its factorization.

21490387216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1236 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 43.

The spelling of 21490387216 in words is "twenty-one billion, four hundred ninety million, three hundred eighty-seven thousand, two hundred sixteen".