20399644731 has 8 divisors (see below), whose sum is σ = 27211618624. Its totient is φ = 13593717000.

The previous prime is 20399644567. The next prime is 20399644753. The reversal of 20399644731 is 13744699302.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20399644731 - 2¹⁵ = 20399611963 is a prime.

It is a super-2 number, since 2×20399644731² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20399644231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1503661 + ... + 1517166.

It is an arithmetic number, because the mean of its divisors is an integer number (3401452328).

Almost surely, 2^20399644731 is an apocalyptic number.

20399644731 is a deficient number, since it is larger than the sum of its proper divisors (6811973893).

20399644731 is a wasteful number, since it uses less digits than its factorization.

20399644731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3023081.

The product of its (nonzero) digits is 979776, while the sum is 48.

The spelling of 20399644731 in words is "twenty billion, three hundred ninety-nine million, six hundred forty-four thousand, seven hundred thirty-one".