21420013031 has 4 divisors (see below), whose sum is σ = 22158634200. Its totient is φ = 20681391864.

The previous prime is 21420013019. The next prime is 21420013079. The reversal of 21420013031 is 13031002412.

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 21420013031 - 2³⁴ = 4240143847 is a prime.

It is a super-2 number, since 2×21420013031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420013081) 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, 369310541 + ... + 369310598.

It is an arithmetic number, because the mean of its divisors is an integer number (5539658550).

Almost surely, 2^21420013031 is an apocalyptic number.

21420013031 is a deficient number, since it is larger than the sum of its proper divisors (738621169).

21420013031 is an equidigital number, since it uses as much as digits as its factorization.

21420013031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738621168.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21420013031 its reverse (13031002412), we get a palindrome (34451015443).

The spelling of 21420013031 in words is "twenty-one billion, four hundred twenty million, thirteen thousand, thirty-one".