21040023154 has 4 divisors (see below), whose sum is σ = 31560034734. Its totient is φ = 10520011576.

The previous prime is 21040023119. The next prime is 21040023181. The reversal of 21040023154 is 45132004012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20915812129 + 124211025 = 144623^2 + 11145^2 .

It is a super-2 number, since 2×21040023154² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5260005787 + ... + 5260005790.

Almost surely, 2^21040023154 is an apocalyptic number.

21040023154 is a deficient number, since it is larger than the sum of its proper divisors (10520011580).

21040023154 is a wasteful number, since it uses less digits than its factorization.

21040023154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10520011579.

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 21040023154 its reverse (45132004012), we get a palindrome (66172027166).

The spelling of 21040023154 in words is "twenty-one billion, forty million, twenty-three thousand, one hundred fifty-four".