21040782146 has 4 divisors (see below), whose sum is σ = 31561173222. Its totient is φ = 10520391072.

The previous prime is 21040782137. The next prime is 21040782157. The reversal of 21040782146 is 64128704012.

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., 16062774121 + 4978008025 = 126739^2 + 70555^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5260195535 + ... + 5260195538.

Almost surely, 2^21040782146 is an apocalyptic number.

21040782146 is a deficient number, since it is larger than the sum of its proper divisors (10520391076).

21040782146 is a wasteful number, since it uses less digits than its factorization.

21040782146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10520391075.

The product of its (nonzero) digits is 21504, while the sum is 35.

The spelling of 21040782146 in words is "twenty-one billion, forty million, seven hundred eighty-two thousand, one hundred forty-six".