253954515721 has 3 divisors (see below), whose sum is σ = 253955019661. Its totient is φ = 253954011782.

The previous prime is 253954515719. The next prime is 253954515779. The reversal of 253954515721 is 127515459352.

The square root of 253954515721 is 503939.

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 253954515721 - 2¹ = 253954515719 is a prime.

It is a super-2 number, since 2×253954515721² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (253954515701) 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, 251970 + ... + 755908.

Almost surely, 2^253954515721 is an apocalyptic number.

253954515721 is the 503939-th square number.

253954515721 is the 251970-th centered octagonal number.

It is an amenable number.

253954515721 is a deficient number, since it is larger than the sum of its proper divisors (503940).

253954515721 is an frugal number, since it uses more digits than its factorization.

253954515721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1007878 (or 503939 counting only the distinct ones).

The product of its digits is 1890000, while the sum is 49.

Multiplying 253954515721 by its sum of digits (49), we get a square (12443771270329 = 3527573²).

The spelling of 253954515721 in words is "two hundred fifty-three billion, nine hundred fifty-four million, five hundred fifteen thousand, seven hundred twenty-one".