61821657 has 32 divisors (see below), whose sum is σ = 95247360. Its totient is φ = 39588480.

The previous prime is 61821653. The next prime is 61821667. The reversal of 61821657 is 75612816.

It is not a de Polignac number, because 61821657 - 2² = 61821653 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61821653) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 194863 + ... + 195179.

It is an arithmetic number, because the mean of its divisors is an integer number (2976480).

Almost surely, 2^61821657 is an apocalyptic number.

It is an amenable number.

61821657 is a deficient number, since it is larger than the sum of its proper divisors (33425703).

61821657 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (61821656) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (584).

61821657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590 (or 584 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 61821657 is about 7862.6749265120. The cubic root of 61821657 is about 395.4093006717.

The spelling of 61821657 in words is "sixty-one million, eight hundred twenty-one thousand, six hundred fifty-seven".