21621401716154 has 16 divisors (see below), whose sum is σ = 32598330827400. Its totient is φ = 10755425442624.

The previous prime is 21621401716147. The next prime is 21621401716157. The reversal of 21621401716154 is 45161710412612.

It can be written as a sum of positive squares in 4 ways, for example, as 21343688525929 + 277713190225 = 4619923^2 + 526985^2 .

It is a super-3 number, since 3×21621401716154³ (a number of 41 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21621401716157) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33177449 + ... + 33822860.

Almost surely, 2^{21621401716154} is an apocalyptic number.

21621401716154 is a deficient number, since it is larger than the sum of its proper divisors (10976929111246).

21621401716154 is a wasteful number, since it uses less digits than its factorization.

21621401716154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67001137.

The product of its (nonzero) digits is 80640, while the sum is 41.

The spelling of 21621401716154 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred one million, seven hundred sixteen thousand, one hundred fifty-four".