21131070740 has 96 divisors (see below), whose sum is σ = 49261280544. Its totient is φ = 7563386880.

The previous prime is 21131070713. The next prime is 21131070767. The reversal of 21131070740 is 4707013112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21131070713) and next prime (21131070767).

It can be written as a sum of positive squares in 16 ways, for example, as 8984385796 + 12146684944 = 94786^2 + 110212^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2699312 + ... + 2707128.

It is an arithmetic number, because the mean of its divisors is an integer number (513138339).

Almost surely, 2^21131070740 is an apocalyptic number.

21131070740 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 21131070740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24630640272).

21131070740 is an abundant number, since it is smaller than the sum of its proper divisors (28130209804).

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

21131070740 is a wasteful number, since it uses less digits than its factorization.

21131070740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8157 (or 8155 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 26.

Adding to 21131070740 its reverse (4707013112), we get a palindrome (25838083852).

The spelling of 21131070740 in words is "twenty-one billion, one hundred thirty-one million, seventy thousand, seven hundred forty".