29921921 has 4 divisors (see below), whose sum is σ = 31682052. Its totient is φ = 28161792.

The previous prime is 29921911. The next prime is 29921933. The reversal of 29921921 is 12912992.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22193521 + 7728400 = 4711^2 + 2780^2 .

It is a de Polignac number, because none of the positive numbers 2^k-29921921 is a prime.

It is a super-3 number, since 3×29921921³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (29921911) 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, 880040 + ... + 880073.

It is an arithmetic number, because the mean of its divisors is an integer number (7920513).

Almost surely, 2^29921921 is an apocalyptic number.

It is an amenable number.

29921921 is a deficient number, since it is larger than the sum of its proper divisors (1760131).

29921921 is a wasteful number, since it uses less digits than its factorization.

29921921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760130.

The product of its digits is 5832, while the sum is 35.

The square root of 29921921 is about 5470.0933264433. The cubic root of 29921921 is about 310.4534501662.

It can be divided in two parts, 2992 and 1921, that added together give a cube (4913 = 17³).

The spelling of 29921921 in words is "twenty-nine million, nine hundred twenty-one thousand, nine hundred twenty-one".