1221021101531 has 32 divisors (see below), whose sum is σ = 1554991423488. Its totient is φ = 931027940640.

The previous prime is 1221021101473. The next prime is 1221021101533. The reversal of 1221021101531 is 1351011201221.

It is not a de Polignac number, because 1221021101531 - 2¹⁸ = 1221020839387 is a prime.

It is a super-2 number, since 2×1221021101531² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221021101533) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21406856 + ... + 21463818.

It is an arithmetic number, because the mean of its divisors is an integer number (48593481984).

Almost surely, 2^{1221021101531} is an apocalyptic number.

1221021101531 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221021101531 is a deficient number, since it is larger than the sum of its proper divisors (333970321957).

1221021101531 is a wasteful number, since it uses less digits than its factorization.

1221021101531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62951.

The product of its (nonzero) digits is 120, while the sum is 20.

Adding to 1221021101531 its reverse (1351011201221), we get a palindrome (2572032302752).

The spelling of 1221021101531 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one hundred one thousand, five hundred thirty-one".