21397591995 has 16 divisors (see below), whose sum is σ = 36869697312. Its totient is φ = 10534199040.

The previous prime is 21397591961. The next prime is 21397592023. The reversal of 21397591995 is 59919579312.

It is not a de Polignac number, because 21397591995 - 2¹⁷ = 21397460923 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54865426 + ... + 54865815.

It is an arithmetic number, because the mean of its divisors is an integer number (2304356082).

Almost surely, 2^21397591995 is an apocalyptic number.

21397591995 is a deficient number, since it is larger than the sum of its proper divisors (15472105317).

21397591995 is a wasteful number, since it uses less digits than its factorization.

21397591995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109731262.

The product of its digits is 6889050, while the sum is 60.

The spelling of 21397591995 in words is "twenty-one billion, three hundred ninety-seven million, five hundred ninety-one thousand, nine hundred ninety-five".