21651455031 has 4 divisors (see below), whose sum is σ = 28868606712. Its totient is φ = 14434303352.

The previous prime is 21651454999. The next prime is 21651455093. The reversal of 21651455031 is 13055415612.

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 21651455031 - 2⁵ = 21651454999 is a prime.

It is a super-2 number, since 2×21651455031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21651454983 and 21651455001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21651455531) 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, 3608575836 + ... + 3608575841.

It is an arithmetic number, because the mean of its divisors is an integer number (7217151678).

Almost surely, 2^21651455031 is an apocalyptic number.

21651455031 is a deficient number, since it is larger than the sum of its proper divisors (7217151681).

21651455031 is an equidigital number, since it uses as much as digits as its factorization.

21651455031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7217151680.

The product of its (nonzero) digits is 18000, while the sum is 33.

The spelling of 21651455031 in words is "twenty-one billion, six hundred fifty-one million, four hundred fifty-five thousand, thirty-one".