21257348401 has 3 divisors (see below), whose sum is σ = 21257494201. Its totient is φ = 21257202602.

The previous prime is 21257348353. The next prime is 21257348417. The reversal of 21257348401 is 10484375212.

The square root of 21257348401 is 145799.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 21257348401 - 2⁹ = 21257347889 is a prime.

It is a super-2 number, since 2×21257348401² (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 (21257348461) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 72900 + ... + 218698.

Almost surely, 2^21257348401 is an apocalyptic number.

21257348401 is the 145799-th square number.

21257348401 is the 72900-th centered octagonal number.

It is an amenable number.

21257348401 is a deficient number, since it is larger than the sum of its proper divisors (145800).

21257348401 is an frugal number, since it uses more digits than its factorization.

21257348401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291598 (or 145799 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 37.

The spelling of 21257348401 in words is "twenty-one billion, two hundred fifty-seven million, three hundred forty-eight thousand, four hundred one".