1651605521 has 8 divisors (see below), whose sum is σ = 1708101120. Its totient is φ = 1595999808.

The previous prime is 1651605497. The next prime is 1651605523. The reversal of 1651605521 is 1255061561.

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

It is a cyclic number.

It is not a de Polignac number, because 1651605521 - 2¹⁸ = 1651343377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1651605523) 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, 218696 + ... + 226121.

It is an arithmetic number, because the mean of its divisors is an integer number (213512640).

Almost surely, 2^1651605521 is an apocalyptic number.

It is an amenable number.

1651605521 is a deficient number, since it is larger than the sum of its proper divisors (56495599).

1651605521 is an equidigital number, since it uses as much as digits as its factorization.

1651605521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444943.

The product of its (nonzero) digits is 9000, while the sum is 32.

The square root of 1651605521 is about 40639.9498154218. The cubic root of 1651605521 is about 1182.0488967626.

The spelling of 1651605521 in words is "one billion, six hundred fifty-one million, six hundred five thousand, five hundred twenty-one".