21520157274 has 112 divisors (see below), whose sum is σ = 60340944960. Its totient is φ = 5589622080.

The previous prime is 21520157273. The next prime is 21520157279. The reversal of 21520157274 is 47275102512.

21520157274 is a `hidden beast` number, since 2 + 15 + 2 + 0 + 1 + 572 + 74 = 666.

It is a super-2 number, since 2×21520157274² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21520157273) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 16422 + ... + 208110.

Almost surely, 2^21520157274 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21520157274, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30170472480).

21520157274 is an abundant number, since it is smaller than the sum of its proper divisors (38820787686).

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

21520157274 is a wasteful number, since it uses less digits than its factorization.

21520157274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191727 (or 191712 counting only the distinct ones).

The product of its (nonzero) digits is 39200, while the sum is 36.

Adding to 21520157274 its reverse (47275102512), we get a palindrome (68795259786).

The spelling of 21520157274 in words is "twenty-one billion, five hundred twenty million, one hundred fifty-seven thousand, two hundred seventy-four".