21521155331 has 8 divisors (see below), whose sum is σ = 23494117920. Its totient is φ = 19593548352.

The previous prime is 21521155309. The next prime is 21521155333. The reversal of 21521155331 is 13355112512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21521155331 - 2¹⁰ = 21521154307 is a prime.

It is a super-2 number, since 2×21521155331² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21521155294 and 21521155303.

It is not an unprimeable number, because it can be changed into a prime (21521155333) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11337911 + ... + 11339808.

It is an arithmetic number, because the mean of its divisors is an integer number (2936764740).

Almost surely, 2^21521155331 is an apocalyptic number.

21521155331 is a deficient number, since it is larger than the sum of its proper divisors (1972962589).

21521155331 is a wasteful number, since it uses less digits than its factorization.

21521155331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22677805.

The product of its digits is 4500, while the sum is 29.

Adding to 21521155331 its reverse (13355112512), we get a palindrome (34876267843).

The spelling of 21521155331 in words is "twenty-one billion, five hundred twenty-one million, one hundred fifty-five thousand, three hundred thirty-one".