21997337901 has 96 divisors (see below), whose sum is σ = 39191733504. Its totient is φ = 10705305600.

The previous prime is 21997337899. The next prime is 21997337909. The reversal of 21997337901 is 10973379912.

It is a happy number.

It is not a de Polignac number, because 21997337901 - 2¹ = 21997337899 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21997337909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10409421 + ... + 10411533.

It is an arithmetic number, because the mean of its divisors is an integer number (408247224).

Almost surely, 2^21997337901 is an apocalyptic number.

21997337901 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21997337901 is a deficient number, since it is larger than the sum of its proper divisors (17194395603).

21997337901 is a wasteful number, since it uses less digits than its factorization.

21997337901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2403 (or 2392 counting only the distinct ones).

The product of its (nonzero) digits is 642978, while the sum is 51.

The spelling of 21997337901 in words is "twenty-one billion, nine hundred ninety-seven million, three hundred thirty-seven thousand, nine hundred one".