21508267754 has 4 divisors (see below), whose sum is σ = 32262401634. Its totient is φ = 10754133876.

The previous prime is 21508267751. The next prime is 21508267783. The reversal of 21508267754 is 45776280512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19950150025 + 1558117729 = 141245^2 + 39473^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21508267699 and 21508267708.

It is not an unprimeable number, because it can be changed into a prime (21508267751) by changing a digit.

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, 5377066937 + ... + 5377066940.

Almost surely, 2^21508267754 is an apocalyptic number.

21508267754 is a deficient number, since it is larger than the sum of its proper divisors (10754133880).

21508267754 is a wasteful number, since it uses less digits than its factorization.

21508267754 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10754133879.

The product of its (nonzero) digits is 940800, while the sum is 47.

The spelling of 21508267754 in words is "twenty-one billion, five hundred eight million, two hundred sixty-seven thousand, seven hundred fifty-four".