21542031007 has 16 divisors (see below), whose sum is σ = 24854349312. Its totient is φ = 18289144800.

The previous prime is 21542030987. The next prime is 21542031011. The reversal of 21542031007 is 70013024512.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21542031007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542031107) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 337413 + ... + 396145.

It is an arithmetic number, because the mean of its divisors is an integer number (1553396832).

Almost surely, 2^21542031007 is an apocalyptic number.

21542031007 is a deficient number, since it is larger than the sum of its proper divisors (3312318305).

21542031007 is a wasteful number, since it uses less digits than its factorization.

21542031007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59238.

The product of its (nonzero) digits is 1680, while the sum is 25.

Adding to 21542031007 its reverse (70013024512), we get a palindrome (91555055519).

The spelling of 21542031007 in words is "twenty-one billion, five hundred forty-two million, thirty-one thousand, seven".