21661044542654 has 32 divisors (see below), whose sum is σ = 35644883328000. Its totient is φ = 9790506887040.

The previous prime is 21661044542653. The next prime is 21661044542713. The reversal of 21661044542654 is 45624544016612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661044542653) 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, 104052179 + ... + 104260145.

It is an arithmetic number, because the mean of its divisors is an integer number (1113902604000).

Almost surely, 2^{21661044542654} is an apocalyptic number.

21661044542654 is a deficient number, since it is larger than the sum of its proper divisors (13983838785346).

21661044542654 is a wasteful number, since it uses less digits than its factorization.

21661044542654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234608.

The product of its (nonzero) digits is 5529600, while the sum is 50.

The spelling of 21661044542654 in words is "twenty-one trillion, six hundred sixty-one billion, forty-four million, five hundred forty-two thousand, six hundred fifty-four".