21171023154 has 48 divisors (see below), whose sum is σ = 46197499608. Its totient is φ = 7006887936.

The previous prime is 21171023143. The next prime is 21171023183. The reversal of 21171023154 is 45132017112.

It can be written as a sum of positive squares in 4 ways, for example, as 18871341129 + 2299682025 = 137373^2 + 47955^2 .

It is a super-3 number, since 3×21171023154³ (a number of 32 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1459224 + ... + 1473660.

Almost surely, 2^21171023154 is an apocalyptic number.

21171023154 is an abundant number, since it is smaller than the sum of its proper divisors (25026476454).

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

21171023154 is a wasteful number, since it uses less digits than its factorization.

21171023154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15019 (or 15016 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The spelling of 21171023154 in words is "twenty-one billion, one hundred seventy-one million, twenty-three thousand, one hundred fifty-four".