21661042555410 has 32 divisors (see below), whose sum is σ = 52012124015040. Its totient is φ = 5773431139008.

The previous prime is 21661042555337. The next prime is 21661042555463. The reversal of 21661042555410 is 1455524016612.

It is a happy 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, 177867852 + ... + 177989591.

It is an arithmetic number, because the mean of its divisors is an integer number (1625378875470).

Almost surely, 2^{21661042555410} is an apocalyptic number.

21661042555410 is an abundant number, since it is smaller than the sum of its proper divisors (30351081459630).

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

21661042555410 is a wasteful number, since it uses less digits than its factorization.

21661042555410 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355859482.

The product of its (nonzero) digits is 288000, while the sum is 42.

The spelling of 21661042555410 in words is "twenty-one trillion, six hundred sixty-one billion, forty-two million, five hundred fifty-five thousand, four hundred ten".