21006663254 has 8 divisors (see below), whose sum is σ = 32180420448. Its totient is φ = 10279856440.

The previous prime is 21006663221. The next prime is 21006663259. The reversal of 21006663254 is 45236660012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006663259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111737477 + ... + 111737664.

It is an arithmetic number, because the mean of its divisors is an integer number (4022552556).

Almost surely, 2^21006663254 is an apocalyptic number.

21006663254 is a deficient number, since it is larger than the sum of its proper divisors (11173757194).

21006663254 is a wasteful number, since it uses less digits than its factorization.

21006663254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223475190.

The product of its (nonzero) digits is 51840, while the sum is 35.

The spelling of 21006663254 in words is "twenty-one billion, six million, six hundred sixty-three thousand, two hundred fifty-four".