21201031154 has 16 divisors (see below), whose sum is σ = 32675173848. Its totient is φ = 10309554432.

The previous prime is 21201031139. The next prime is 21201031169. The reversal of 21201031154 is 45113010212.

It is an interprime number because it is at equal distance from previous prime (21201031139) and next prime (21201031169).

It can be written as a sum of positive squares in 4 ways, for example, as 13662103225 + 7538927929 = 116885^2 + 86827^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 113642 + ... + 235194.

Almost surely, 2^21201031154 is an apocalyptic number.

21201031154 is a deficient number, since it is larger than the sum of its proper divisors (11474142694).

21201031154 is a wasteful number, since it uses less digits than its factorization.

21201031154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123949.

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21201031154 its reverse (45113010212), we get a palindrome (66314041366).

The spelling of 21201031154 in words is "twenty-one billion, two hundred one million, thirty-one thousand, one hundred fifty-four".