21172784682 has 16 divisors (see below), whose sum is σ = 48394936512. Its totient is φ = 6049367040.

The previous prime is 21172784681. The next prime is 21172784683. The reversal of 21172784682 is 28648727112.

It is an interprime number because it is at equal distance from previous prime (21172784681) and next prime (21172784683).

It is a super-2 number, since 2×21172784682² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21172784681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 252056919 + ... + 252057002.

It is an arithmetic number, because the mean of its divisors is an integer number (3024683532).

Almost surely, 2^21172784682 is an apocalyptic number.

21172784682 is an abundant number, since it is smaller than the sum of its proper divisors (27222151830).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21172784682 is a wasteful number, since it uses less digits than its factorization.

21172784682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504113933.

The product of its digits is 602112, while the sum is 48.

The spelling of 21172784682 in words is "twenty-one billion, one hundred seventy-two million, seven hundred eighty-four thousand, six hundred eighty-two".