21040300391 has 16 divisors (see below), whose sum is σ = 23122844448. Its totient is φ = 18986572800.

The previous prime is 21040300381. The next prime is 21040300409. The reversal of 21040300391 is 19300304012.

It is a cyclic number.

It is not a de Polignac number, because 21040300391 - 2⁶ = 21040300327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040300301) 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, 817085 + ... + 842441.

It is an arithmetic number, because the mean of its divisors is an integer number (1445177778).

Almost surely, 2^21040300391 is an apocalyptic number.

21040300391 is a deficient number, since it is larger than the sum of its proper divisors (2082544057).

21040300391 is a wasteful number, since it uses less digits than its factorization.

21040300391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25922.

The product of its (nonzero) digits is 648, while the sum is 23.

The spelling of 21040300391 in words is "twenty-one billion, forty million, three hundred thousand, three hundred ninety-one".