21150204034661 has 16 divisors (see below), whose sum is σ = 23444926439424. Its totient is φ = 18957420849024.

The previous prime is 21150204034541. The next prime is 21150204034667. The reversal of 21150204034661 is 16643040205112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21150204034661 is a prime.

It is a super-2 number, since 2×21150204034661² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21150204034667) 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, 136204760 + ... + 136359953.

It is an arithmetic number, because the mean of its divisors is an integer number (1465307902464).

Almost surely, 2^{21150204034661} is an apocalyptic number.

It is an amenable number.

21150204034661 is a deficient number, since it is larger than the sum of its proper divisors (2294722404763).

21150204034661 is a wasteful number, since it uses less digits than its factorization.

21150204034661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272564900.

The product of its (nonzero) digits is 34560, while the sum is 35.

Adding to 21150204034661 its reverse (16643040205112), we get a palindrome (37793244239773).

The spelling of 21150204034661 in words is "twenty-one trillion, one hundred fifty billion, two hundred four million, thirty-four thousand, six hundred sixty-one".