21732405786 has 160 divisors (see below), whose sum is σ = 60052164480. Its totient is φ = 5720367744.

The previous prime is 21732405733. The next prime is 21732405869. The reversal of 21732405786 is 68750423712.

21732405786 is a `hidden beast` number, since 2 + 1 + 7 + 32 + 40 + 578 + 6 = 666.

It is a super-2 number, since 2×21732405786² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 9713860 + ... + 9716096.

It is an arithmetic number, because the mean of its divisors is an integer number (375326028).

Almost surely, 2^21732405786 is an apocalyptic number.

21732405786 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21732405786, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30026082240).

21732405786 is an abundant number, since it is smaller than the sum of its proper divisors (38319758694).

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

21732405786 is a wasteful number, since it uses less digits than its factorization.

21732405786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2930 (or 2921 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The spelling of 21732405786 in words is "twenty-one billion, seven hundred thirty-two million, four hundred five thousand, seven hundred eighty-six".