21661044602654 has 8 divisors (see below), whose sum is σ = 32491729420608. Its totient is φ = 10830468129120.

The previous prime is 21661044602611. The next prime is 21661044602657. The reversal of 21661044602654 is 45620644016612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21661044602599 and 21661044602608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661044602657) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26584427 + ... + 27387110.

It is an arithmetic number, because the mean of its divisors is an integer number (4061466177576).

Almost surely, 2^{21661044602654} is an apocalyptic number.

21661044602654 is a deficient number, since it is larger than the sum of its proper divisors (10830684817954).

21661044602654 is a wasteful number, since it uses less digits than its factorization.

21661044602654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54172210.

The product of its (nonzero) digits is 1658880, while the sum is 47.

The spelling of 21661044602654 in words is "twenty-one trillion, six hundred sixty-one billion, forty-four million, six hundred two thousand, six hundred fifty-four".