31221477 has 24 divisors (see below), whose sum is σ = 53808000. Its totient is φ = 17840088.

The previous prime is 31221473. The next prime is 31221493. The reversal of 31221477 is 77412213.

It is a happy number.

It is not a de Polignac number, because 31221477 - 2² = 31221473 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 31221477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31221473) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10477 + ... + 13122.

It is an arithmetic number, because the mean of its divisors is an integer number (2242000).

Almost surely, 2^31221477 is an apocalyptic number.

It is an amenable number.

31221477 is a deficient number, since it is larger than the sum of its proper divisors (22586523).

31221477 is a wasteful number, since it uses less digits than its factorization.

31221477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23622 (or 23609 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 31221477 is about 5587.6181866695. The cubic root of 31221477 is about 314.8844020278.

The spelling of 31221477 in words is "thirty-one million, two hundred twenty-one thousand, four hundred seventy-seven".