21506205447274 has 4 divisors (see below), whose sum is σ = 32259308170914. Its totient is φ = 10753102723636.

The previous prime is 21506205447229. The next prime is 21506205447299. The reversal of 21506205447274 is 47274450260512.

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., 11580511090225 + 9925694357049 = 3403015^2 + 3150507^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5376551361817 + ... + 5376551361820.

Almost surely, 2^{21506205447274} is an apocalyptic number.

21506205447274 is a deficient number, since it is larger than the sum of its proper divisors (10753102723640).

21506205447274 is a wasteful number, since it uses less digits than its factorization.

21506205447274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10753102723639.

The product of its (nonzero) digits is 3763200, while the sum is 49.

The spelling of 21506205447274 in words is "twenty-one trillion, five hundred six billion, two hundred five million, four hundred forty-seven thousand, two hundred seventy-four".