21154563043 has 4 divisors (see below), whose sum is σ = 21156117640. Its totient is φ = 21153008448.

The previous prime is 21154562963. The next prime is 21154563107. The reversal of 21154563043 is 34036545112.

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

It is a cyclic number.

It is not a de Polignac number, because 21154563043 - 2⁹ = 21154562531 is a prime.

It is a super-2 number, since 2×21154563043² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154564043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 756705 + ... + 784162.

It is an arithmetic number, because the mean of its divisors is an integer number (5289029410).

Almost surely, 2^21154563043 is an apocalyptic number.

21154563043 is a deficient number, since it is larger than the sum of its proper divisors (1554597).

21154563043 is a wasteful number, since it uses less digits than its factorization.

21154563043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1554596.

The product of its (nonzero) digits is 43200, while the sum is 34.

The spelling of 21154563043 in words is "twenty-one billion, one hundred fifty-four million, five hundred sixty-three thousand, forty-three".