21346256553 has 32 divisors (see below), whose sum is σ = 31989365760. Its totient is φ = 12595746240.

The previous prime is 21346256483. The next prime is 21346256573. The reversal of 21346256553 is 35565264312.

It is a happy number.

It is not a de Polignac number, because 21346256553 - 2¹⁰ = 21346255529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21346256573) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 132958 + ... + 245703.

It is an arithmetic number, because the mean of its divisors is an integer number (999667680).

Almost surely, 2^21346256553 is an apocalyptic number.

21346256553 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21346256553 is a deficient number, since it is larger than the sum of its proper divisors (10643109207).

21346256553 is a wasteful number, since it uses less digits than its factorization.

21346256553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378749.

The product of its digits is 648000, while the sum is 42.

The spelling of 21346256553 in words is "twenty-one billion, three hundred forty-six million, two hundred fifty-six thousand, five hundred fifty-three".