401721251 has 4 divisors (see below), whose sum is σ = 402180192. Its totient is φ = 401262312.

The previous prime is 401721227. The next prime is 401721277. The reversal of 401721251 is 152127104.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 401721251 - 2²² = 397526947 is a prime.

It is a super-2 number, since 2×401721251² = 322759927010010002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (401721851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228155 + ... + 229908.

It is an arithmetic number, because the mean of its divisors is an integer number (100545048).

Almost surely, 2^401721251 is an apocalyptic number.

401721251 is a deficient number, since it is larger than the sum of its proper divisors (458941).

401721251 is an equidigital number, since it uses as much as digits as its factorization.

401721251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458940.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 401721251 is about 20042.9850820680. The cubic root of 401721251 is about 737.8616445616.

Adding to 401721251 its reverse (152127104), we get a palindrome (553848355).

The spelling of 401721251 in words is "four hundred one million, seven hundred twenty-one thousand, two hundred fifty-one".