61221637 has 4 divisors (see below), whose sum is σ = 62645440. Its totient is φ = 59797836.

The previous prime is 61221631. The next prime is 61221649. The reversal of 61221637 is 73612216.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61221637 - 2¹¹ = 61219589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61221631) 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, 711837 + ... + 711922.

It is an arithmetic number, because the mean of its divisors is an integer number (15661360).

Almost surely, 2^61221637 is an apocalyptic number.

It is an amenable number.

61221637 is a deficient number, since it is larger than the sum of its proper divisors (1423803).

61221637 is a wasteful number, since it uses less digits than its factorization.

61221637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423802.

The product of its digits is 3024, while the sum is 28.

The square root of 61221637 is about 7824.4256658237. The cubic root of 61221637 is about 394.1259034874.

The spelling of 61221637 in words is "sixty-one million, two hundred twenty-one thousand, six hundred thirty-seven".