21661211511310 has 32 divisors (see below), whose sum is σ = 47181395160000. Its totient is φ = 6989836319232.

The previous prime is 21661211511301. The next prime is 21661211511323. The reversal of 21661211511310 is 1311511216612.

It is a super-2 number, since 2×21661211511310² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9101348185 + ... + 9101350564.

It is an arithmetic number, because the mean of its divisors is an integer number (1474418598750).

Almost surely, 2^{21661211511310} is an apocalyptic number.

21661211511310 is an abundant number, since it is smaller than the sum of its proper divisors (25520183648690).

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

21661211511310 is a wasteful number, since it uses less digits than its factorization.

21661211511310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18202698780.

The product of its (nonzero) digits is 2160, while the sum is 31.

Adding to 21661211511310 its reverse (1311511216612), we get a palindrome (22972722727922).

The spelling of 21661211511310 in words is "twenty-one trillion, six hundred sixty-one billion, two hundred eleven million, five hundred eleven thousand, three hundred ten".