1211506389645 has 16 divisors (see below), whose sum is σ = 1941993249792. Its totient is φ = 644942399040.

The previous prime is 1211506389589. The next prime is 1211506389647. The reversal of 1211506389645 is 5469836051121.

It is not a de Polignac number, because 1211506389645 - 2¹⁶ = 1211506324109 is a prime.

It is a super-3 number, since 3×1211506389645³ (a number of 37 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211506389647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74637997 + ... + 74654226.

It is an arithmetic number, because the mean of its divisors is an integer number (121374578112).

Almost surely, 2^{1211506389645} is an apocalyptic number.

1211506389645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1211506389645 is a deficient number, since it is larger than the sum of its proper divisors (730486860147).

1211506389645 is a wasteful number, since it uses less digits than its factorization.

1211506389645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149292772.

The product of its (nonzero) digits is 1555200, while the sum is 51.

The spelling of 1211506389645 in words is "one trillion, two hundred eleven billion, five hundred six million, three hundred eighty-nine thousand, six hundred forty-five".