21167829540 has 216 divisors, whose sum is σ = 76006936824. Its totient is φ = 4736793600.

The previous prime is 21167829523. The next prime is 21167829577. The reversal of 21167829540 is 4592876112.

21167829540 is a `hidden beast` number, since 2 + 1 + 16 + 78 + 29 + 540 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 8054244 + 21159775296 = 2838^2 + 145464^2 .

It is a super-2 number, since 2×21167829540² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 245760 + ... + 320520.

Almost surely, 2^21167829540 is an apocalyptic number.

21167829540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21167829540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38003468412).

21167829540 is an abundant number, since it is smaller than the sum of its proper divisors (54839107284).

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

21167829540 is a wasteful number, since it uses less digits than its factorization.

21167829540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74811 (or 74795 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The spelling of 21167829540 in words is "twenty-one billion, one hundred sixty-seven million, eight hundred twenty-nine thousand, five hundred forty".