42640521 has 48 divisors (see below), whose sum is σ = 72573312. Its totient is φ = 21795840.

The previous prime is 42640517. The next prime is 42640553. The reversal of 42640521 is 12504624.

It is not a de Polignac number, because 42640521 - 2² = 42640517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42640491 and 42640500.

It is not an unprimeable number, because it can be changed into a prime (42640511) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 246391 + ... + 246563.

It is an arithmetic number, because the mean of its divisors is an integer number (1511944).

Almost surely, 2^42640521 is an apocalyptic number.

It is an amenable number.

42640521 is a deficient number, since it is larger than the sum of its proper divisors (29932791).

42640521 is a wasteful number, since it uses less digits than its factorization.

42640521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 42640521 is about 6529.9709800274. The cubic root of 42640521 is about 349.3607952362.

It can be divided in two parts, 426405 and 21, that added together give a triangular number (426426 = T₉₂₃).

The spelling of 42640521 in words is "forty-two million, six hundred forty thousand, five hundred twenty-one".