21520155351412 has 6 divisors (see below), whose sum is σ = 37660271864978. Its totient is φ = 10760077675704.

The previous prime is 21520155351389. The next prime is 21520155351553. The reversal of 21520155351412 is 21415355102512.

It can be written as a sum of positive squares in only one way, i.e., 21401319336336 + 118836015076 = 4626156^2 + 344726^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690019418923 + ... + 2690019418930.

Almost surely, 2^{21520155351412} is an apocalyptic number.

It is an amenable number.

21520155351412 is a deficient number, since it is larger than the sum of its proper divisors (16140116513566).

21520155351412 is a wasteful number, since it uses less digits than its factorization.

21520155351412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5380038837857 (or 5380038837855 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 37.

The spelling of 21520155351412 in words is "twenty-one trillion, five hundred twenty billion, one hundred fifty-five million, three hundred fifty-one thousand, four hundred twelve".