21149639730 has 128 divisors (see below), whose sum is σ = 57574022400. Its totient is φ = 5523144192.

The previous prime is 21149639723. The next prime is 21149639737. The reversal of 21149639730 is 3793694112.

21149639730 is a `hidden beast` number, since 2 + 1 + 1 + 4 + 9 + 639 + 7 + 3 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21149639723) and next prime (21149639737).

It is a super-3 number, since 3×21149639730³ (a number of 32 digits) contains 333 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21149639737) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4410214 + ... + 4415006.

It is an arithmetic number, because the mean of its divisors is an integer number (449797050).

Almost surely, 2^21149639730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21149639730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28787011200).

21149639730 is an abundant number, since it is smaller than the sum of its proper divisors (36424382670).

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

21149639730 is a wasteful number, since it uses less digits than its factorization.

21149639730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5145 (or 5139 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 45.

The spelling of 21149639730 in words is "twenty-one billion, one hundred forty-nine million, six hundred thirty-nine thousand, seven hundred thirty".